Mystery solenoid

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Darkimag22

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1998 GMC Sierra SLT 5.7L Z71

Slowly but surely working my way through the electrical system in my truck. At one point it had dual batteries (found and removed the isolator since I have a new Cole Hersee unit on order) which also tied into a distro style block and a solenoid. Any idea what it might be for??? It leads straight down and under the truck rearward. I couldn't trace it since the underside of my truck is still a huge block of snow and ice (thanks to -43C weather here in northern Alberta). I disconnected it and nothing seems to be disrupted. Any ideas??? Just wanting to tidy things up under the hood.
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Vanishing Point

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Slowly but surely working my way through the electrical system in my truck. At one point it had dual batteries (found and removed the isolator since I have a new Cole Hersee unit on order) which also tied into a distro style block and a solenoid. Any idea what it might be for??? It leads straight down and under the truck rearward. I couldn't trace it since the underside of my truck is still a huge block of snow and ice (thanks to -43C weather here in northern Alberta). I disconnected it and nothing seems to be disrupted. Any ideas??? Just wanting to tidy things up under the hood.
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Vanishing Point

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Can you give us more information regarding your vehicle's year, make, and model. So I'll make a wild @ss guess, by the looks of your avatar, you either have a GMT 400 OBS 1996-99 GMC ECSB/ECLB C1500 or C2500, and it seems at one time to be connected to an extra 12-volt battery,(dual battery) setup as you stated earlier or could be for a lift gate, or air compressor leading to back and bed of your truck.
It also looks like someone has cut some wires! I would assume that was you!
It sure makes it challenging to say what this three terminal 12volt solenoid was connected to at one time to make run. Without more info on your part, it is very tough to say. So until the snow melts keep us posted.
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thinger2

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Yep. it could also have been used to run camper lights or trailer lights or to charge camper batteries.
Also could be used for auxilliary backup lights.
Like tractor lights.
Do you have any mystery dash switches or battery isolater switches?
 

GoToGuy

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Is it an intermittent or continuous duty solenoid. Either way those are for high amp high load. Is this a case where it should have been a relay? Those don't appear to be high amperage capacity wires.
 

Darkimag22

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Can you give us more information regarding your vehicle's year, make, and model. So I'll make a wild @ss guess, by the looks of your avatar, you either have a GMT 400 OBS 1996-99 GMC ECSB/ECLB C1500 or C2500, and it seems at one time to be connected to an extra 12-volt battery,(dual battery) setup as you stated earlier or could be for a lift gate, or air compressor leading to back and bed of your truck.
It also looks like someone has cut some wires! I would assume that was you!
It sure makes it challenging to say what this three terminal 12volt solenoid was connected to at one time to make run. Without more info on your part, it is very tough to say. So until the snow melts keep us posted.
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My signature has all my truck info :). This is how I found it..cut wires and everything. It was still connected to the dual battery isolator which I removed already. I'll have to take another look underneath and see what I can see since I was able to park it inside to thaw overnight.
Is it an intermittent or continuous duty solenoid. Either way those are for high amp high load. Is this a case where it should have been a relay? Those don't appear to be high amperage capacity wires.
How do I tell the difference? The wiring is maybe 12 gauge if that. I'm in the process of doing the BIG 3 running all 2/0 welding cable (perks of working in a welding shop).
Yep. it could also have been used to run camper lights or trailer lights or to charge camper batteries.
Also could be used for auxilliary backup lights.
Like tractor lights.
Do you have any mystery dash switches or battery isolater switches?
The weird thing is there are no mystery switches, lights, nothing. It did, at one time, have a remote starter installed but it was removed sometime before I bought the truck last spring. There are a few spliced wires under the dash that seem to lead no where.
 

tpass

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It isn't factory, so anything said now is just a guess as to what it was used for, unless you know the previous owner that installed it.
 

GoToGuy

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If take 15 seconds to lead your post with year, make, model, eng size. Your are guaranteed to get more and accurate replies than if you expect everyone to dig through your "about me" to find your truck. Many of us have multiple GM vehicles. I have 2 GMT trucks. A 98 tahoe. 91 shortbed stepside. And 86 K3500 dually. I look at it if my post is difficult or lazy, who wants to reply?
Good luck.
 

evilunclegrimace

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If take 15 seconds to lead your post with year, make, model, eng size. Your are guaranteed to get more and accurate replies than if you expect everyone to dig through your "about me" to find your truck. Many of us have multiple GM vehicles. I have 2 GMT trucks. A 98 tahoe. 91 shortbed stepside. And 86 K3500 dually. I look at it if my post is difficult or lazy, who wants to reply?
Good luck.
His year make and model are directly under the picture that he posted, no digging required.:33:
 
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