Hello everyone,
I have a 2001 Yukon Denali and am having a problem with the taillights on my trailer. I have hooked up a few trailers to the truck, and they all have the same problem. All the lights function as they should except for the taillights on the trailer.
I am using the GM adaptor so I can use my regular 4-pin connection on the trailer.
Does anyone have any ideas as to what I should check? Thanks very much in advance for any help on the matter.
Check the fuse box under the hood. There should be a 15amp fuse in there who's sole purpose is trailer running lights. Bob
Do you have a 7 pin connector on the Yukon? Then adapt to a 4 pin?
This is the wiring for both 7 and 4 pin.
So you see your adapter should connect the tail light pin 3 on the 7 pin to the brown on the 4 pin.
A check with a meter or a test light between the brown and white wires on the adapter will tell you if you are getting power to those points. Also should be between pin 3 and 1 on a 7 pin connector.
Note that the diagram is looking into the back of the connector.
If you are getting power to the plug then you should check to make sure you have a good ground. If trailer is not ground well through the trailer hitch and ground through the plug then your lights will not work. Check both power from the vehicle with a volt meter or a test light sold at automotive stores. If the power is good then the problem is with the trailer. If you have no power trace the wires back and find a place to see if is connected. If you have one of those tail light conversion boxes the problem could be in there. Check fuses.
Check the ground on the trailer and make sure it is not corroded.
Sarge
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