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Username Post: The single starter power wire behind the engine...        (Topic#365979)
Stylingpat 
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Posts: 99
Stylingpat
Reg: 08-21-15
08-02-21 08:37 AM - Post#2824297    

Anyone who's worked on any c1500's knows about the single thin starter wire going from the wire harness (on the driver side of the engine) down to the starter, is a thin wrapped wire laying across the top of the transmission and behind the engine.

After 380k miles, the wrap wore away, vibrated the wire bare and was shorting me out.

I wrapped the wire with electrical tape... you cant freaking see the thing... the whole project is blind behind the engine... and got expensive heat wrap, and wrapped the entire wire from top to starter.. I'm not shorting out anymore..

But I am now soaking up heat after that job. Once the truck runs for a while and the wire soaks up enough heat, I will build up resistance, enough that if I shut the truck off, I wont be able to restart it for 20 mins until the wire cools off.

Anyone deal with this crap? You cant see anything back there.



Edited by Stylingpat on 08-02-21 08:38 AM. Reason for edit: No reason given.

 
rockfangd 
"8th Year" Gold Supporting Member
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rockfangd
Age: 35
Loc: Utica ny
Reg: 04-13-10
08-02-21 08:06 PM - Post#2824360    
    In response to Stylingpat

Yes. Fire hazard for sure.
The harness is attached over the transmission from one side to the other. Can you just leave the old cable and run a new one in a convenient spot?

Old School GM fan FOREVER


 
Stylingpat 
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Posts: 99
Stylingpat
Reg: 08-21-15
08-03-21 05:11 AM - Post#2824374    
    In response to rockfangd

  • rockfangd Said:
Yes. Fire hazard for sure.
The harness is attached over the transmission from one side to the other. Can you just leave the old cable and run a new one in a convenient spot?




Oooooo, I dont see why not. Have you done this before?



 
rockfangd 
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rockfangd
Age: 35
Loc: Utica ny
Reg: 04-13-10
08-03-21 08:13 AM - Post#2824384    
    In response to Stylingpat

Yes. I have run new. I run them as close to the original as possible. Others may not.
Crucial to make sure it is not too close to exhaust or chaffing on the engine.


Old School GM fan FOREVER


 
Stylingpat 
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Posts: 99
Stylingpat
Reg: 08-21-15
08-03-21 12:12 PM - Post#2824400    
    In response to rockfangd

Now the "beginning" of the single wire by it self, out of the wiring harness running over the transmission down towards the starter, how far back does it go backway through the harness? Does it just go all the way back to the fuse block and lin up to a pin, all by it self? Because that would be awesome



 
rockfangd 
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rockfangd
Age: 35
Loc: Utica ny
Reg: 04-13-10
08-03-21 12:13 PM - Post#2824401    
    In response to Stylingpat

Should go to the battery. There is a fusible link inline from the battery and it runs back from there.


Old School GM fan FOREVER


 
Stylingpat 
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Posts: 99
Stylingpat
Reg: 08-21-15
08-03-21 01:50 PM - Post#2824405    
    In response to rockfangd

So that single hand grenade of a wire, is always hot and coming from the battery? That's weird, why would they route it around the front of the engine, then around the driver side, then over the back of the transmission down back to the starter (on the passenger side)



 
rockfangd 
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rockfangd
Age: 35
Loc: Utica ny
Reg: 04-13-10
08-03-21 01:58 PM - Post#2824407    
    In response to Stylingpat

Just out of curiosity what color is the wire?
There should be a larger wire that is 12v constant, and a purple iirc crank wire. The small wire that comes off goes to the fuse box.
What year is the truck?
Pre 95 it is up on the passenger side firewall. 95+ should be on the driver side by the ABS unit.
If it is the small wire only then that is just the trigger wire for the starter solenoid. Is 12v when key is turned to crank.
Same deal. You should be able to cut it where you know it is good and eliminate the bad area.

Old School GM fan FOREVER


Edited by rockfangd on 08-03-21 02:00 PM. Reason for edit: No reason given.

 
Stylingpat 
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Posts: 99
Stylingpat
Reg: 08-21-15
08-03-21 02:09 PM - Post#2824408    
    In response to rockfangd

I was always under the impression it was the trigger wire. Its a 1996 with the fuse block up near the driver side firewall. Its a thin wire, its not anything heavy guage



 
rockfangd 
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rockfangd
Age: 35
Loc: Utica ny
Reg: 04-13-10
08-03-21 02:22 PM - Post#2824409    
    In response to Stylingpat

OK. So I believe that wire comes from the starter relay in the underhood fuse box.
I am not surprised of how it is routed.
The harness is a whole unit and the wires come out of it wherever the area they need to be. Sometimes that can be all the way across the engine bey

Old School GM fan FOREVER


 
Stylingpat 
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Posts: 99
Stylingpat
Reg: 08-21-15
08-03-21 03:12 PM - Post#2824411    
    In response to rockfangd

This could be a fun project, how did you do yours?



 
rockfangd 
"8th Year" Gold Supporting Member
Posts: 3146
rockfangd
Age: 35
Loc: Utica ny
Reg: 04-13-10
08-03-21 04:59 PM - Post#2824416    
    In response to Stylingpat

I typically cut the wire back to a known good area, splice in a new wire right to the starter.
Either weatherproof butt splice or crimp with heat shrink insulation

Old School GM fan FOREVER


 
someotherguy 
Senior Moderator
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someotherguy
Loc: Texas
Reg: 08-01-03
08-04-21 05:46 AM - Post#2824441    
    In response to Stylingpat

  • Stylingpat Said:
So that single hand grenade of a wire, is always hot and coming from the battery? That's weird, why would they route it around the front of the engine, then around the driver side, then over the back of the transmission down back to the starter (on the passenger side)


Definitely mixing up the two wires' roles there. The "hand grenade" (good term!) is the larger gauge wire that is fed from the battery to the solenoid, that is always hot. The one you are working with is indeed the "trigger" wire from the ignition switch. That one is only hot when the key is in the "start" position, and it engages the starter solenoid to feed power from the hand grenade wire to the stater motor.

Richard

06 Silverado ISS / 06 Silverado SS / 06 300C SRT8


 
Stylingpat 
Poster
Posts: 99
Stylingpat
Reg: 08-21-15
08-04-21 09:15 AM - Post#2824468    
    In response to someotherguy

Yes! And I just found the problem (havent tested yet, it started raining) the hand grenade wire was pinched between the frame and the exhaust headers, and the wire has some melt on it. I think that's where my heat soak is coming from!! Finally! LOL

Re-wrapped the wire and tomorrow I will find out if electrical gremlin #2 has finally been caught after a few years.

I went and reinspected the trigger wire.. I wrapped it with heat shield, put plastic heat resistant (expensive) cable wrap around it. Its been over a year, job still looks great.

Ol' Betsy 380k miles going to be going from Florida to California and possibly down in to Mexico haha. She's itching for another adventure hahah.

I really really wish I had a thermal camera and I can look at the entire truck warmed up and see whats going on with ALL the electrical connections.

Next job is going through the fuse box and making sure all the pin contacts are nice and tight.



 
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