Testing Auxiliary Power line...

[Mickeyfan0805]

I posted, last week, about installing a new wiring harness. I have successfully done that, but do have 1 remaining issue. I am receiving positive signals with my tester on every line except for the aux power, which shows nothing. So, for those of you more in the know about vehicle wiring (doesn't take much to know more than me!), I have 2 questions.

1) Would/should the aux power lead indicate a positive signal any time the vehicle is on, or is this somehow a passive power that doesn't become active until the trailer is connected?

2) If it SHOULD be giving me a positive signal, where do I locate that fuse and how do I check it (I had two fuses that needed to be replaced in this process)? My owner's manual lists 'STUD #1' as controlling the 'Auxiliary Power' but doesn't mention the trailer. Is that what I am looking for?

Any help would be greatly appreciated.

[Mickeyfan0805]

enblethen wrote:
Some Chev Suburbans and pick ups were stud 1 and some were stud 2.

Thanks everyone. This has been helpful - knowing that I should be showing power in testing and that it is likely one of the Stud fuses has pretty much narrowed it down. Stud 2 is intact but Stud 1 does appear to be burned. I will swap that out as I expect it will solve the problem!

Thanks again.

[enblethen]

Some Chev Suburbans and pick ups were stud 1 and some were stud 2.

[corvettekent]

It would be nice to know what truck you have.

[Mickeyfan0805]

enblethen wrote:
In the same location as Stud 2, should be a thirty amp fuse. Some rigs have a dummy fuse that must be changed to a fuse.
Test with voltmeter or test light.

I'm testing with a standard automotive test light. I'm getting positive signals everywhere but in the Aux Power. I'm guessing it's a fuse, but having trouble figuring out which one it would be. Stud 2 (my first guess) says it controls trailer brake wiring, which is working. I'm now wondering if it is Stud 1, but all that says is 'Auxiliary Power' and doesn't say anything about the trailer.

[enblethen]

In the same location as Stud 2, should be a thirty amp fuse. Some rigs have a dummy fuse that must be changed to a fuse.
Test with voltmeter or test light.