Red 12v wire?? Where does it go
 

1985 gmc k2500 4wd vinM 350ci

Alright driver side of firewall in engine bay there is a 20amp glass fuse. Coming off it is a red 14gauge wire. It's about 3 feet long. It seems like it goes into the cab. It has a constant 12v. Idk where it goes. Can't really find it on the wiring diagram and I'm a little confused with some abbreviations in the wiring diagram. For some reason I think it's 4wd related idk.

Anyone got an idea?
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Re: Red 12v wire?? Where does it go
 

Probably an add on for a stereo or something... GOT A PICTURE ????,
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Re: Red 12v wire?? Where does it go
 

ya thats probably for an amp, cb radio, snow plow, winch....could be anything but its def not factory

Re: Red 12v wire?? Where does it go
 

It's factory wiring. If u look at the wiring diagram "cab interior page 2" u can locate it.
http://www.73-87chevytrucks.com/tech..._V8_engine.jpg

I think it's above generator, then to the right of the generator on the same wire it says k/81 & k/85 only??
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Re: Red 12v wire?? Where does it go
 

Our 86' has that and it's the +12V feed for the trailer wiring.

Re: Red 12v wire?? Where does it go
 

I've got one runs front to back red thick in the harness to the back hitch area
in my 79 jimmy,told it was for the trailer,prob gona put a lighter plug back there using it

Re: Red 12v wire?? Where does it go
 

Camper or heavy duty trailer package:

http://s3d4.turboimagehost.com/t1/16275164_1203049.jpg

Re: Red 12v wire?? Where does it go
 

Thanks everyone very helpful. The trailer hitch idea makes a lot of sence. My truck is a vin M(heavy duty)
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