I have a 2005 Suburban with multiple-lead plug for trailer lights. I use an adapter for hooking to a 4-straight-lead trailer, and when plugged in, the turn signals and brake lights work on the trailer, but not the running lights on the trailer. A friend plugged in the trailer on his Explorer (4 inline leads) and the trailer lights worked fine... so I assume the problem is with my Suburban.

Any ideas what could be going on? I have two identical adapters to go in the plug. I tried both and neither solve the problem.

I checked, and the contracts are clean on the trailer and on my Suburban.

Thanks for any insights. J

Fuses?
Are you getting 12 volt power for tail or running lights at plug in?
Also good ground?

Thanks for the tip(s)... I hadn't considered the possibility that a fuse would prevent the running lights only - from working. I assumed that since the turn signals and brake lights worked, and the running lights on the truck worked, that there would be no problem with fuse(s).

The ground is the same used also for brake lights and turn signals, so I assumed this was not the issue.

With all this said, when I get home from work tonight, I'll be going through this list and checking off each item one-by-one. Guess I'll also try using a multimeter to check current flow from each electrical point.

Thanks again.... J

Thanks for the tip(s)... I hadn't considered the possibility that a fuse would prevent the running lights only - from working. I assumed that since the turn signals and brake lights worked, and the running lights on the truck worked, that there would be no problem with fuse(s).

The ground is the same used also for brake lights and turn signals, so I assumed this was not the issue.

With all this said, when I get home from work tonight, I'll be going through this list and checking off each item one-by-one. Guess I'll also try using a multimeter to check current flow from each electrical point.

Thanks again.... J

A good volt/ohm meter or a old fashion test light with bulb works good.

Did you ever solve this problem? I'm having the exact same problem with my 2004 Suburban. The running lights on the truck work, but not on the trailer. The turn signals/brake lights on the trailer do work. I'm not getting any power on the running lights circuit at the plug-in, so it's a vehicle problem, not a trailer problem. I was trying to check the fuse, but cannot determine the fuse location for the trailer running lights. The fuse panel clearly marks the trailer brake/turn lights, but I can't see where the fuse is for trailer running lights.

Any further insight anyone has on this would be greatly appreciated.

Thanks

Welcome to AF
With a new problem better to start a new post/thread.
http://www.automotiveforums.com/vbulletin/newthread.php?do=newthread&f=1451
The fuse may be called trailer park fuse. Trl/park
Check owners manual for under hood fuse box ID.

I found the fuse -- in the engine compartment. And the fuse was the problem. All fixed! Thanks for your help!

I found the fuse -- in the engine compartment. And the fuse was the problem. All fixed! Thanks for your help!

You are welcome and Thanks for posting back how it went.
MT