04 trailblazer random wire

Buddy of mine has a 2004 Chevy TrailBlazer.

He recently had gotten a aftermarket immobolizer installed (mantatory install thanks to insurance)

We looked under the hood today on an unrelated matter and found a random red wire not attached to anything. 

It looks like it could have come off of one of the posts in the fuse box.

Any idea what this wire is for?

Would this be disconnected due to the aftermarket immobolizer?

it is definitely a factory wire and something tells me it is supposed to be bolted to that post on the corner of the fuse box that you see in the picture. it must go somewhere that it can reach without stretching too much and that it the only place i can see. as for what exactly it does, i havent the slightest clue. are any fuses blown or missing from the fuse box? you should be able to tell if somethings missing by reading the lid for the fuse box.

Does the vehicle have factory driving/fog lights? GM is always doing things like this for options not installed. If no fog lights then most likely the wire goes into the vehicle for the fog light switch and is not hooked up for the switch that is not there. As the main harness is the same for all simular models. To add the lights you would hook up the wire to the corner post and need the harness that goes to the fog lights from the under hood fusebox, the lights with mounts and the head light switch that has the fog switch included, and if I remember correctly a relay. I will take a look at a GMC envoy the equivilent to the trailblazer which has the lights and post back.

maybe battery feed for a trailer connector...7 way connector at rear? see if fuse 32 (30A) feeds the nearby stud.

There looks to be some aftermarket wiring, joins the main loom adjacent to that red wire and runs to the right of the picture below the 125 amp fuse. I concur with that post on the left. Of course the OP could ask the installer.

Also why under the hood? I've done literally hundreds of immobilisers and the only times I've gone under the hood were M/Benz into a fuse box. Can't starter and ignition or fuel pump be grabbed inside where the joints would be more secure?

the manual might tell you what this wire is for.

It was probably never connected from the factory! Just leave it. I see this all the time when installing remote starts. I would only connect after looking at a wire diagram/if something isnt working.

Yea i've noticed that same wire on that body and always wondered what it's for. Leave it alone...Mike M2

Tech Manager

CS Dealer Services

Ween wrote: maybe battery feed for a trailer connector...7 way connector at rear? see if fuse 32 (30A) feeds the nearby stud.

This.

GM leaves always leaves the trailer battery feed disconnected.