TV Wiring issues...help!

[lbrownah]

Long story short, we had a 2007 Yukon Denali but for financial reasons, had to downgrade for the time being and sold it (for a profit, no less, after almost two years!)

Were looking at older and fortunate to get a 2007 regular Yukon for a great price. So, in anticipation of heading out in a couple days again, was smart enough to go down to the where the trailer is stored to check on it and make sure the new TV is a similar setup for hitch height etc, being basically the same truck.

Well, good thing we did...the hitch height on the regular Yukon looks to be an inch and a half or so higher, as the Argosy's power jack couldn't "recoil" far enough up after getting to the bottom. Through a longer story, we were lucky that we got an adjustable hitch from the previous owner when we bought the Argosy a few months ago. However, the nuts and bolt on those hitches are heavy duty and the wrench I had with me, so it will get adjusted hopefully at the hitch shop tomorrow when they reinstall my brake controller.

The bigger issue though lays with the electrical. Had no problem with the Denali and the trailer plug. Sure, had to jiggle it a bit to get it in, but worked no problem. The "new" TV, an issue. Same model (almost) same year, same plug etc. Plug it in and the backup lights turn on dimly on the TV, and, no other lights except the Argosy's back lights are on. Blinkers don't work on the Argosy or the running lights on the front.

Read a bit on the net that it could be a faulty ground.

I think I can go under the safe assumption that the issue is with this particular tow vehicle.

THe one x-factor here, at least for me, is that the TV's previous owner put in HID headlights. I have an email out to him asking him if he did it or a shop did, but regardless, not knowing enough about HID, anytime there's electrical work done, there's always the chance that wiring was crossed up somewhere, grounds were changed, fuses blown or whatever.

Not being that handy electrically, and not having a testing meter, not sure where to go. Will take it to the GM dealer and hopefully they can fix it, but in advance of that, any ideas. It can't be the trailer plug, it worked fine the 5 times we've had the trailer out with the previous vehicle.

So is it:
A bad TV electrical receiver plug?
Mixed up wires from the electical plug? (modified when TV got HID's?)
A short in the system?
A blown fuse in the TV? Likely not, I assume that electrical plug runs off a single fuse, and since there is a light that comes on (meaning some power is getting to the trailer)

Help..hopefully it is an easy fix. Cutting it close for leaving in a couple days, and if dealer can't take a look at it or figure out what the issue is...

TIA