99 Yukon Trailer Wiring Question

[kredfearn]

I just bought a 99 Yukon and have a problem with the trailer wiring. When I hooked up my utility trailer for the first time with the headlights off both turn signals on the trailer worked fine, but when I turn on the headlights with the left or right signal on both side marker lights and turn signals on the trailer will flash at the same time. I took off the aftermarket 6 pole round connector because I thought it was the problem and replaced it with the T connector that plugs into the wiring harness and still have the same problem. I checked the wiring with the wiring diagram and everything looks good. Is there something I'm overlooking or need to buy to fix the problem.

 

[GMCYukalade]

humph.. that is a problem.. it only happens when you turn the headlights on? that means that the taillights are messing with the wiring somehow - how does the wiring on the trailer look? are the bulbs in the trailer the one wire type? if so that may be the problem... i do belive they need to be two wire - one for tails.. one for signal.. othewise when you turn the taillights on (1 wire runs both tails) when you hit either of the signals the power is gonna cary across both tails because of the tail light wire - so only way to fix that would be to have a seperate wire in the bulb to carry the signal lights voltage so the signal lights current would never touch the tail lights current - i had a problem sort-of like this on an old truck of mine, id turn one signal on, and all 4 come on like the 4-ways.. no fix for that -- i mean i don't know how the tail lights are wired on the kon.. but if each tail light runs from a seperate power lead (which i really don't think they do) then it would be as simple as running the other tail light power down to the harness and attaching a new wire to the tail light on the trailer - but that probably wouldn't be probabal... i would also think.. that if it is doing that, than both signals on the kon would blink as well.. but.. maybe not.. humph.. - i'm going to say that it is probably a wiring problem on the trailer.. - if there is any chance of you trying the trailer on a diff vehicle.. or trying the kon on a diff trailer.. just to make sure.. ?

 

[kredfearn]

Problem Solved :thumbsup: ... It turned out to be the trailer side marker light’s shorting into the signal wires. I re-wired them and all lights work. Thanks for the info!!

 

[GMCYukalade]

No problem.. i figured it had to be something with the trailer... glad it all worked out for ya