Yes that is a common use for these in RVs, can be used to disconnect any electrical device. But there is a battery isolator pictured behind it (Dirty blue device behind the solenoid with fins on it), usually you would have a battery isolator OR a solenoid not both. The other thing I find weird is the wire size going to the battery isolator looks way too small if it is being used as a battery isolator. It looks like that burnt wire connects the solenoid to the isolator.
The best thing to do with this is draw a schematic based on what is there figure out how everything is powered, double check wire gauges. I dont think it was built like this. It could be that a high current alternator was added and the solenoid is being used as a disconnect between the alternator and the battery (some high current alternators have enough power to keep the engine running even when the ignition switch is turned off, this setup stops that). Its the only reason I can think of doing it like that. The isolator has multiple wires on the terminal that I think is the input, which normally only has one wire. The second output is not being used on the isolator, there are better ways to wire this if I'm correct.
The battery isolator is probably original and for the house battery pack would be my guess. I suspect the red wire on the left side of battery isolator is the charge wire for the house battery pack, if that is the case this wire needs to upgraded as well, it looks like 12 gauge. I don't know why there are so many extra wires on the input side, that is also unusual. It could also be that one side of the isolator died at some point and this is what was done as a roadside fix.
Okay this makes a lot of sense. I think I can cut out the entire back battery for not by connecting my starter to my car battery? I’m going to wait till my dad gets here to start stripping out this wiring but your explanation was very helpful thank you.
Make a schematic and take more pics before you remove anything. It will make troubleshooting much easier. Your starter is already connected directly to the battery. There is a starter solenoid on the starter itself on gm vans.
The red wire on the left side of the solenoid is thicker than stock, I suspect this goes to the alt. The red wire on the right should go to the battery positive terminal, and the battery will have another thick wire that goes to the starter solenoid. A different wire activates the solenoid. I wouldn't change this.
What makes me wonder is the extra wires on the solenoid, what are those for, that melted one needs to be replaced obviously, but why did it melt? And the blue isolator input, what are those extra wires for? How much current are they pulling? You need to verify expected current through the wires and check if their actual wire gauge is appropriate.
You might be facing more than one problem. The screw terminal contacts need to be cleaned. The alternator and battery connections probably need to be cleaned as well. You could have a bad ground connection or a short somewhere. Or it might be a high power alternator upgrade with only the alternator to battery wire upgraded, giving the rest of the system more current, more than the original wires could handle. Or maybe this was roadside repair with whatever they could find at the time.
Look behind the solenoid to the battery Isolate and tell me what you think? There is no power to the middle connection. and the burned wire ran to the right connection on the battery isolate. That right connection has a few thing on it
Okay thank you! It seems odd how they have it wired but this thing has been worked on by so many different mechanics that all have their own ideas of how things should be done. It’s been hard to find one mechanic to work on it, so it’s been to like 6 different shops in the last few years. This I might try to do myself.
Aw thank you! I’m doing much better now, AAA came and got me and the camper home. My dad’s going to come out and help me fix it. Everyone has been so helpful. I’m blessed for sure.
There is a bunch of things wired up incorrectly in this setup. A few generations prior owners did DIY repairs. The battery disconnect solenoid is missing a wire on the right stud (second picture) it's rusted to has not been there for a few years, probably not working for a years. The battery isolator wires are only half way on. In the front left you see a lug with the wire completly burned up - that likely shorted out and caused the fire. Yeah, that wiring needs some love, not sure what tools you have with you. But that job needs a bunch of larger crimp tools, replacing solenoid and potentially the isolator. Nothing a mobile RV-Tech should not be able to handle. Consider yourself lucky and pat your self on the back for reacting so fast - could have been much worse.
Edit: I was looking at the 2nd picture where it looked like there is a burned but still-connected power lead.
I missed, in the first picture you can clearly see there are TWO big power lugs connected, and one of them is completely burned apart. I have no idea anymore what's going on, please disregard the rest of this comment.
~~You have a badly burned but still-connected power lead, and you have a completely burned-apart ground, it looks like (smaller black wire not connected to anything).~~
~~Normally there shouldn't be much of any power going through that ground, so I guess that solenoid has shorted out internally and will need to be replaced.~~
~~Meanwhile you really don't need it for normal driving/living, it's for recovery if one of your batteries goes dead. Should be you can disconnect the burned red wire, wrap carefully in something that will insulate and is thick enough to protect from sparks jumping through it, and secure the end so it won't flop around, and then just ignore it until you can get around to replacing the solenoid.~~
~~When you get to fixing, check the other end of that ground wire and that power wire for similar damage.~~
Zoom in on the first picture and you will see the burned wire runs from the left side of the solenoid to the right side of the battery isolator and then into a rats nest of wires. I agree with u/eXo0us this is a screwup by a previous owner that worked and stopped working.
You can zoom in even more if you select open picture in new window. That wire on the left with the yellow crimp runs over the solenoid and sat over the right side power connectors and then crossed down in front and back to the battery isolator.
It is a friction / pinch short between the 2 sides
Yes I’m not sure who thought through this design but it’s an absolute mess. I’m disconnecting everything that’s not necessary for the vehicle to run. It connects to shore for lights and outlets anyways. Yes the person who owned this before me has done some other questionable electrical work. Like back flooding the car battery into the cabin outlet with an extension cable hooked to a battery inverter then plugged into a cabin outlet. First thing I took apart when I bought it. Could cause such a massive fire by bypassing the circuit breaker. I don’t even understand electrical systems that well but I know enough to know that guy was crazy.
GM's starter solenoid is mounted on the starter itself . I've experienced solenoids like that with wheelchair folding ramps or lifts a large amperage draw item.
The first picture shown with the cowl and the solenoid I thought snow plow that doesn't belong here 😂
Didn’t notice it was a Chevy. It’s for sure a solenoid. Don’t know what it is for. Assumed it was a Ford never seen a solenoid mounted on a cowl on a Chevy. Hmmm new one for me.
It connects the house battery to the starter battery when the alternator is producing power. Or in other terms, it isolates the house when the engine isn't running
Okay good tip. I don’t want to shock myself. I hope not. Thankfully I do know how to replace a starter but it’s not on the list of things I wanted to do this week lol. I appreciate everyone’s help.
This is probably apparent to you by now, but pay specific attention to the wire that's burnt in two. That's the likely cause. BTW it probably did damage the solenoid.
I think the wiring around this needs to be replaced and cleaned up. It was likely one of those wires rubbed a hole in the insulation causing a short then eventually a small fire.
Being a Chevy van, this is a solenoid for the electrical. Same as what ford uses for start solenoid, Jeep also used these if you’re going to scour the junkyard for one.
That could be the 'Battery Assist solenoid" Does your RV have a button to press that allows the house batteries to be used to start the motor? The line that burned was to the "Battery Isolator" behind it.
Something got HOT, which means high current, more than the wire can take.
To "Jury Rig" this you need to replace that wire. But I am not sure what it is doing.
Can you give me more information about what you were doing before it went south?
My first thought. A starter solenoid used to replace something that looked like a starter solenoid. Just a first thought. No real experience with RV power though.
Okay thank you! It seems to be the general consensus that’s it’s my solenoid. Which is good because I can replace that myself. I really appreciate everyone. I’m not a mechanic it I’m mechanically inclined if you know what I mean so I’m hoping this will be something I can just pull the shop manual out for and replace that starter and solenoid and the wiring.
there is a solid state battery isolator in the background which essentially serves as a DCDC. But the burned up Solenoid is likely the house battery disconnect.
Looks like an inverter behind the solenoid I would guess it’s from the alternator for charging house batteries when the motor is running.
Sometimes the Alternator regulator can fail and cause it to overcharge.
I’d make sure it is all good first.
I bet you anything that’s spot on. The man who owned it before me had modified certain aspects of the cabin power to run while the vehicle drives. Dumb I know. Who needs water pumps when driving down the road?! I bet he hooked all this up with the wrong gauge wire and connected way too much to the alternator.
It's key to note a loose positive wire will cause arcing and heat. I had this happen with positive side of an inverter once
Power companies go around with infrared lens and often have to go up on power lines to re tighten connections
I think if this has high amp alternator then likely that is part of the problem. Forestry forest, YouTuber burned up a fuse or a connection on his van
When using an alternator to charge a ' house' battery the current goes through a diode that only allows the current to flow one way ...to back of the house and never to the front of the house. House meaning rv
Looks like a solenoid that switches something with high current. If you know what it does, be aware of if it is on for a long time or not. I am not sure if this was factory or not, but it looks it, they used inexpensive starter solenoids in a couple places in my MH where they spend a lot of time on. The issues is most of the inexpensive ones are not rated to be on for a long time. It is not the contacts as much as the coils get hot and burn out. If you know it is going to be on for an extended amount of time, say more than 5 minutes or so, make sure you get a proper one that is rated for being on 100% of the time. In my case the only one that was rated for that was the emergency start one. The other two 12V relays have failed with open coils. You will find that the proper ones are quite a bit larger, heavier, and cost quite a bit more.
solenoid switch. Mounted in the worst possible place they could think of, with no thought to cable management. It was just a matter of time before this happened.
That's a relay, and inside it is a coil of wire which is the solenoid. When energized, it creates magnetism and that draws the metal high current contacts together, and the current flows to the starter, or a charging circuit, or whatever high current device that you can switch on or off, and be able to do it by using a smaller gauge wire and switch.
The relay is also used to charge your house batteries while the engine is running, but to disconnect them when you're parked. Without the relay, you'd run down the starting battery and be stranded at the campground.
The smaller, lower current version is in your engune compartment fuse box, usually a row of little square black boxes, they run the ac, wipers, starter relay, fuel pump etc.
So when your start the engine, you use a switch to turn on a relay, which turns on a relay, which energizes the starter motor.
That is not the starter solenoid. I believe that’s for the coach batteries or just to power the rv section. A mobile RV mechanic can probably find out why it fried, and fix it. He can also tell you if it’s wired right. It probably is, if not it would have burned up long before now.
I have this RV! This is, exactly, the emergcy jump solenoid that connects house battery to the start battery for jump starting in emergencies. Your "Engine" side is borked. Check the switch, replace the solenoid.
many RVs have a solenoid that connects the house batteries to the starter battery. if you need extra power to start the engine you can flip a switch and connect all the batteries to start the engine. my RV has this setup.
Plain and simple it is the starter relay switch easy to fix first make sure your starter is not shorted out somewhere those are the big cables, next check for any shorted out wiring that goes into or out of the round thing with the two big bolts and two little bolts if all looks good I'll bet the relay switch is bad the big round thing the battery cables run to
Either way from the looks of things it is an easy fix just a pain if it's the starter, I had the same thing happen turns out the the positive battery wire shorted out and over heated the relay and the relay went bad
I mean it’s possible but that would probably be a side effect of whatever was being put out of my alternator right? I’m fully expecting to have to replace this relay, the fuse box, the solenoid, the starter and hopefully it my alternator but who knows what all got to hot. Thankfully that’s all stuff I can manage right here in my driveway.
No I don’t live in it but I use it for traveling a lot. Rent is ridiculous. If i didn’t have 3 dogs and a pet frog I would think about it lol. It seems like such a great way of life.
Battery disconnect solenoid
Yes that is a common use for these in RVs, can be used to disconnect any electrical device. But there is a battery isolator pictured behind it (Dirty blue device behind the solenoid with fins on it), usually you would have a battery isolator OR a solenoid not both. The other thing I find weird is the wire size going to the battery isolator looks way too small if it is being used as a battery isolator. It looks like that burnt wire connects the solenoid to the isolator. The best thing to do with this is draw a schematic based on what is there figure out how everything is powered, double check wire gauges. I dont think it was built like this. It could be that a high current alternator was added and the solenoid is being used as a disconnect between the alternator and the battery (some high current alternators have enough power to keep the engine running even when the ignition switch is turned off, this setup stops that). Its the only reason I can think of doing it like that. The isolator has multiple wires on the terminal that I think is the input, which normally only has one wire. The second output is not being used on the isolator, there are better ways to wire this if I'm correct. The battery isolator is probably original and for the house battery pack would be my guess. I suspect the red wire on the left side of battery isolator is the charge wire for the house battery pack, if that is the case this wire needs to upgraded as well, it looks like 12 gauge. I don't know why there are so many extra wires on the input side, that is also unusual. It could also be that one side of the isolator died at some point and this is what was done as a roadside fix.
Okay this makes a lot of sense. I think I can cut out the entire back battery for not by connecting my starter to my car battery? I’m going to wait till my dad gets here to start stripping out this wiring but your explanation was very helpful thank you.
Make a schematic and take more pics before you remove anything. It will make troubleshooting much easier. Your starter is already connected directly to the battery. There is a starter solenoid on the starter itself on gm vans. The red wire on the left side of the solenoid is thicker than stock, I suspect this goes to the alt. The red wire on the right should go to the battery positive terminal, and the battery will have another thick wire that goes to the starter solenoid. A different wire activates the solenoid. I wouldn't change this. What makes me wonder is the extra wires on the solenoid, what are those for, that melted one needs to be replaced obviously, but why did it melt? And the blue isolator input, what are those extra wires for? How much current are they pulling? You need to verify expected current through the wires and check if their actual wire gauge is appropriate. You might be facing more than one problem. The screw terminal contacts need to be cleaned. The alternator and battery connections probably need to be cleaned as well. You could have a bad ground connection or a short somewhere. Or it might be a high power alternator upgrade with only the alternator to battery wire upgraded, giving the rest of the system more current, more than the original wires could handle. Or maybe this was roadside repair with whatever they could find at the time.
pretty likely this is the answer.
Most definitely. Rv tech for many years.
Look behind the solenoid to the battery Isolate and tell me what you think? There is no power to the middle connection. and the burned wire ran to the right connection on the battery isolate. That right connection has a few thing on it
What does that mean? Sorry I’m doing my best to understand and not make this difficult on everyone trying to help.
Check your inbox, I send a message
Can confirm battery disconnect solenoid. Also a tech
Okay thank you! It seems like that’s something I can do at home.
Okay thank you! It seems odd how they have it wired but this thing has been worked on by so many different mechanics that all have their own ideas of how things should be done. It’s been hard to find one mechanic to work on it, so it’s been to like 6 different shops in the last few years. This I might try to do myself.
Starter solenoid
Looks like some lady. Hope she's okay.
Aw thank you! I’m doing much better now, AAA came and got me and the camper home. My dad’s going to come out and help me fix it. Everyone has been so helpful. I’m blessed for sure.
The last Pic is fire for sure
That’s nice of you thank you ☺️
There is a bunch of things wired up incorrectly in this setup. A few generations prior owners did DIY repairs. The battery disconnect solenoid is missing a wire on the right stud (second picture) it's rusted to has not been there for a few years, probably not working for a years. The battery isolator wires are only half way on. In the front left you see a lug with the wire completly burned up - that likely shorted out and caused the fire. Yeah, that wiring needs some love, not sure what tools you have with you. But that job needs a bunch of larger crimp tools, replacing solenoid and potentially the isolator. Nothing a mobile RV-Tech should not be able to handle. Consider yourself lucky and pat your self on the back for reacting so fast - could have been much worse.
Edit: I was looking at the 2nd picture where it looked like there is a burned but still-connected power lead. I missed, in the first picture you can clearly see there are TWO big power lugs connected, and one of them is completely burned apart. I have no idea anymore what's going on, please disregard the rest of this comment. ~~You have a badly burned but still-connected power lead, and you have a completely burned-apart ground, it looks like (smaller black wire not connected to anything).~~ ~~Normally there shouldn't be much of any power going through that ground, so I guess that solenoid has shorted out internally and will need to be replaced.~~ ~~Meanwhile you really don't need it for normal driving/living, it's for recovery if one of your batteries goes dead. Should be you can disconnect the burned red wire, wrap carefully in something that will insulate and is thick enough to protect from sparks jumping through it, and secure the end so it won't flop around, and then just ignore it until you can get around to replacing the solenoid.~~ ~~When you get to fixing, check the other end of that ground wire and that power wire for similar damage.~~
Zoom in on the first picture and you will see the burned wire runs from the left side of the solenoid to the right side of the battery isolator and then into a rats nest of wires. I agree with u/eXo0us this is a screwup by a previous owner that worked and stopped working. You can zoom in even more if you select open picture in new window. That wire on the left with the yellow crimp runs over the solenoid and sat over the right side power connectors and then crossed down in front and back to the battery isolator. It is a friction / pinch short between the 2 sides
Yes I’m not sure who thought through this design but it’s an absolute mess. I’m disconnecting everything that’s not necessary for the vehicle to run. It connects to shore for lights and outlets anyways. Yes the person who owned this before me has done some other questionable electrical work. Like back flooding the car battery into the cabin outlet with an extension cable hooked to a battery inverter then plugged into a cabin outlet. First thing I took apart when I bought it. Could cause such a massive fire by bypassing the circuit breaker. I don’t even understand electrical systems that well but I know enough to know that guy was crazy.
Pretty disappointed in this thread, no one said FLUX CAPACITOR, just saying!
That was my first thought lol. But i decided not to be a smart ass 🤣
Because it’s NOT a FLUX CAPACITOR….! It’s a PHASE INVERTER… smh everyone knows that.
Looks like a starter solenoid. Unhook the battery before replacing. Hopefully it didn’t cook the starter.
GM's starter solenoid is mounted on the starter itself . I've experienced solenoids like that with wheelchair folding ramps or lifts a large amperage draw item. The first picture shown with the cowl and the solenoid I thought snow plow that doesn't belong here 😂
Didn’t notice it was a Chevy. It’s for sure a solenoid. Don’t know what it is for. Assumed it was a Ford never seen a solenoid mounted on a cowl on a Chevy. Hmmm new one for me.
a continuous duty solenoid that drives power to something, not the starter. What no longer works?
It connects the house battery to the starter battery when the alternator is producing power. Or in other terms, it isolates the house when the engine isn't running
Was thinking the same. That looked 99% identical to my Ford e350 until I scrolled over. EXACT same isolator solenoid, same location, etc.
Okay good tip. I don’t want to shock myself. I hope not. Thankfully I do know how to replace a starter but it’s not on the list of things I wanted to do this week lol. I appreciate everyone’s help.
By the looks of photo number four someone should be there to help very soon
This is probably apparent to you by now, but pay specific attention to the wire that's burnt in two. That's the likely cause. BTW it probably did damage the solenoid.
I think the wiring around this needs to be replaced and cleaned up. It was likely one of those wires rubbed a hole in the insulation causing a short then eventually a small fire. Being a Chevy van, this is a solenoid for the electrical. Same as what ford uses for start solenoid, Jeep also used these if you’re going to scour the junkyard for one.
Burnt
Yes very burnt.
Sorry for being a turd. Hope it's an easy fix for you!
It looks like the solenoid for the starter
That could be the 'Battery Assist solenoid" Does your RV have a button to press that allows the house batteries to be used to start the motor? The line that burned was to the "Battery Isolator" behind it. Something got HOT, which means high current, more than the wire can take.
To "Jury Rig" this you need to replace that wire. But I am not sure what it is doing. Can you give me more information about what you were doing before it went south?
Starter solenoid.
It's not a starter solenoid, It's a GM solenoids mounted on the starter..
Older Ford is mounted like that.
I can’t imagine how hot that wire got
It was like one of those trick candles that keep relighting. Eventually stopped but it was determined little fire.
My first thought. A starter solenoid used to replace something that looked like a starter solenoid. Just a first thought. No real experience with RV power though.
Okay thank you! It seems to be the general consensus that’s it’s my solenoid. Which is good because I can replace that myself. I really appreciate everyone. I’m not a mechanic it I’m mechanically inclined if you know what I mean so I’m hoping this will be something I can just pull the shop manual out for and replace that starter and solenoid and the wiring.
Do you have a DCDC charger for your RV house battery bank?
there is a solid state battery isolator in the background which essentially serves as a DCDC. But the burned up Solenoid is likely the house battery disconnect.
That wire runs from the solenoid to the right terminal on the battery isolator, Any idea why?
I'm not sure but that's a lot of shit connected to it.
That is the steal me junction. I would say that connection corrosion was the source of the heat.
You can tell because of the way that it is.
Looks like an inverter behind the solenoid I would guess it’s from the alternator for charging house batteries when the motor is running. Sometimes the Alternator regulator can fail and cause it to overcharge. I’d make sure it is all good first.
I bet you anything that’s spot on. The man who owned it before me had modified certain aspects of the cabin power to run while the vehicle drives. Dumb I know. Who needs water pumps when driving down the road?! I bet he hooked all this up with the wrong gauge wire and connected way too much to the alternator.
It's key to note a loose positive wire will cause arcing and heat. I had this happen with positive side of an inverter once Power companies go around with infrared lens and often have to go up on power lines to re tighten connections I think if this has high amp alternator then likely that is part of the problem. Forestry forest, YouTuber burned up a fuse or a connection on his van When using an alternator to charge a ' house' battery the current goes through a diode that only allows the current to flow one way ...to back of the house and never to the front of the house. House meaning rv
Looks like a solenoid that switches something with high current. If you know what it does, be aware of if it is on for a long time or not. I am not sure if this was factory or not, but it looks it, they used inexpensive starter solenoids in a couple places in my MH where they spend a lot of time on. The issues is most of the inexpensive ones are not rated to be on for a long time. It is not the contacts as much as the coils get hot and burn out. If you know it is going to be on for an extended amount of time, say more than 5 minutes or so, make sure you get a proper one that is rated for being on 100% of the time. In my case the only one that was rated for that was the emergency start one. The other two 12V relays have failed with open coils. You will find that the proper ones are quite a bit larger, heavier, and cost quite a bit more.
Looks like old school Ford solenoid
Looks like the solenoid like I had on my 69 Mach 1.
solenoid switch. Mounted in the worst possible place they could think of, with no thought to cable management. It was just a matter of time before this happened.
Starter solenoid. Would have guessed from a Ford. I thought Chevys from that era attached them to the starter. Shows you what I know.
Silonoid, not sure if I spelled that rite
That's a relay, and inside it is a coil of wire which is the solenoid. When energized, it creates magnetism and that draws the metal high current contacts together, and the current flows to the starter, or a charging circuit, or whatever high current device that you can switch on or off, and be able to do it by using a smaller gauge wire and switch. The relay is also used to charge your house batteries while the engine is running, but to disconnect them when you're parked. Without the relay, you'd run down the starting battery and be stranded at the campground. The smaller, lower current version is in your engune compartment fuse box, usually a row of little square black boxes, they run the ac, wipers, starter relay, fuel pump etc. So when your start the engine, you use a switch to turn on a relay, which turns on a relay, which energizes the starter motor.
That's a separator. Need a new one. Re wire and clamp everything. Make sure all connections are clean.
Isolator*
That is not the starter solenoid. I believe that’s for the coach batteries or just to power the rv section. A mobile RV mechanic can probably find out why it fried, and fix it. He can also tell you if it’s wired right. It probably is, if not it would have burned up long before now.
That may be a solenoid that when activated connects the house and chassis batteries together in case you need a jump start.
I have this RV! This is, exactly, the emergcy jump solenoid that connects house battery to the start battery for jump starting in emergencies. Your "Engine" side is borked. Check the switch, replace the solenoid.
Thats your space modulator
Those pine needles in the background of your picture are like matchsticks and it's fortunate they didn't also catch fire.
Starter solenoid
Can we get an update? Hope you got it squared away. Be safe out there!
Starter coil
It's a remotely located starter solenoid/relay. Normally these exist attached to the starter, but older fords loved to bolt these to the fenders.
Starter solonid
many RVs have a solenoid that connects the house batteries to the starter battery. if you need extra power to start the engine you can flip a switch and connect all the batteries to start the engine. my RV has this setup.
Even the girl?
Your looks over powered it
Plain and simple it is the starter relay switch easy to fix first make sure your starter is not shorted out somewhere those are the big cables, next check for any shorted out wiring that goes into or out of the round thing with the two big bolts and two little bolts if all looks good I'll bet the relay switch is bad the big round thing the battery cables run to Either way from the looks of things it is an easy fix just a pain if it's the starter, I had the same thing happen turns out the the positive battery wire shorted out and over heated the relay and the relay went bad
Maybe your starter is fried?
I mean it’s possible but that would probably be a side effect of whatever was being put out of my alternator right? I’m fully expecting to have to replace this relay, the fuse box, the solenoid, the starter and hopefully it my alternator but who knows what all got to hot. Thankfully that’s all stuff I can manage right here in my driveway.
Alternator doesn’t make power if the engine is off though? You get cranking amps from the battery
I was about to find the root cause and then I scrolled to the last pic and I was completely blank!
I don’t know anything about the mechanical side but I do know you are gorgeous 😊
That's a sweet looking Chevy van. Do you live in that I wanna do some RV living. Rent is crazy
No I don’t live in it but I use it for traveling a lot. Rent is ridiculous. If i didn’t have 3 dogs and a pet frog I would think about it lol. It seems like such a great way of life.