Trailer Light Problem, need help!

[fsutim]

When towing my trailer everything works great until my headlights are turned on. When the headlights are on both my left and right lights light up completely, then when I press the brakes both right and left trailer lights turn off and go completely dark until I let go of the brakes. When I turn either the left or right turn signal on both turn signals blink at the same time, like I have my hazard lights on. From what I have seen on the board it looks like it could be a ground problem? I currently have the ground wire that comes from the 4 prong hookup bolted down to the tongue of my trailer. Should I be running more grounds than this one? Any ideas other than this being a ground problem? Any suggestions would be greatly appreciated! FYI, I have a 7 way to 4 pin adapter hooked up between my chevy tahoe and the trailer.

 

[Silvertip]

Re: Trailer Light Problem, need help!

Those darned adapters cause more problems than they are worth. You first need to make sure the terminals on that adapter are providing the functions required. If that end is ok, then look at grounding on the trailer. Does your Tahoe have amber turn signals by any chance? If so, you need a converter as the truck and trailer lighting systems are not compatible.

 

[DrCox]

Re: Trailer Light Problem, need help!

I have a 2002 GMC Yukon that I tow with. identical in most repsects to your Tahoe. I also have the 7-4 adapter but my adapter has 3 little LED lights that are built in testers to ensure the lights are woking right at that location even if trailer is not hooked up.
If yours does not have this I would suggest you buy a plug in tester (4.99 at GiJoes) that way you can make sure its from the trailer back, not on your rig. Once you half Step troubleshoot it, then you can continue from there. Hope this helps.

-DrCox

 

[reelfishin]

Re: Trailer Light Problem, need help!

I have had to add ground wires from my trailer tongue to main trailer frame on all of my tilt type trailers and those with non welded tongue/frame rails.

First check to see if you have all the proper voltages coming from the adapter, make sure the adapter ground is good, then if all is well, try taking a jumper cable and grounding the main frame or what ever the lights mount too.
Also make sure the light assemblies are in good shape as well.

 

[mthieme]

Re: Trailer Light Problem, need help!

I've seen this before when the wires were not connected for the intended function.
This URL will tell you what wire goes where...
http://www.accessconnect.com/trailer_wiring_diagram.htm

 

[DrCox]

Re: Trailer Light Problem, need help!

Man..

You guys are NOT going to believe this. I went to pick up the restoration project today. Trailer had no lights so I picked up a pair from the local marine store. Nothing fancy just brake/turn signal combo (x2).

Followed wire diagram posted above, only zip tied them down for temp runiing lights. Plugged into the 4 prong adapter and guess what> Lights were all jacked up. When headlights are on right light completly out, Right flasher does not work. only thing that works is emergency flashers.

headlights off, everything works fine.

Now I am confused

Sorry, I am not hijacking your post but you have a Tahoe, I have a yukon and now we are both having light issues...What gives>?


-DrCox

 

[mthieme]

Re: Trailer Light Problem, need help!

That's interesting since the models are so close - probably the same under the skin.
For what it's worth,
I had a Chevy S10...no problems.
But it had a factory inline 4 connector (S10 with a towing package ???).
Whenever possible, I try to get wiring harness which plugs into the taillights. They seem to have less issues as oppossed to tapping into wherever you can.

fsutim - curious - have you double checked the wiring (yet).