Trailer harness question

[rolfsent]

Okay I checked underneath my Denali and it has a blue wire and a orange wire not connected to anything. I connected my new harness and spliced my harness into the blue wire, which is supposed to be the reverse lights. I checked the plug with a multimeter and all pins have power except the blue reverse. I have checked and rechecked the connections. Any idea on what is wrong?

 

[SunlitComet]

Yes according to the service manual the reverse lights wire is Light Green. The blue wire commonly know as auxiliary wire is typically used for electric brake controllers but at time of vehicle build the front end of blue wire is end cut and taped on body underneath the under hood fuse block. Also there is no orange wire in the harness. perhaps it is the color faded red wire which normally taps to the extra studs at underhood fuse block as well. Also not connected when built.

 

[rolfsent]

Yes according to the service manual the reverse lights wire is Light Green. The blue wire commonly know as auxiliary wire is typically used for electric brake controllers but at time of vehicle build the front end of blue wire is end cut and taped on body underneath the under hood fuse block. Also there is no orange wire in the harness. perhaps it is the color faded red wire which normally taps to the extra studs at underhood fuse block as well. Also not connected when built.

So can I just take the taillight out and splice my trailer harness wire into it?

 

[SunlitComet]

there should be a plug setup under the body already. like the c409 in pic below.

C409
C400-C499

Notes

Camper And Trailer Wiring

Notes

Tail And Stoplamp Harness

 

[the big blue bus]

the wire is orange im pretty suire can get pics tomorrow. you want to find the light green wire under the truck forthe reverse function your talking about. mine was connected under the hood

 

[rolfsent]

I found the light green wire and spliced it into my harness and now I have no reverse lights. All other lights work.

 

[SunlitComet]

did you short out the fuse in the process?

 

[rolfsent]

Where is the reverse light fuse?

 

[SunlitComet]

turn b/u fuse #16 20 amp. I/P block.

 

[rolfsent]

I checked fuse 16 and it's good. I replaced the reverse bulbs and they still don't work. I get power to the reverse on the trailer harness now though. So I have no idea what to do next.