Trailer light problem

[GABassin]

Just curious if anyone in here has ever experienced this or knows how to fix it. My running lights on my trailer stopped working out of the blue. The stop and turn still work ok but just the running lights when my truck lights are on is not working. Any help would be greatly appreciated. Thank you

[BigBassGuy]

Check and clean ALL connections, also make sure you have a proper ground between the trailer and vehicle

[Dad_Golf_Fish]

You probably have a two filament bulb. One for the brake/turn which is brighter and one for the running/parking light. The chance of that filament going on both bulbs at the same time is a little remote (unless you back in with the trailer lights still connected).

I would start at the connector to the vehicle and make sure you have a good connection there. If so, a pen type voltage tester (wire tester) from the connector back to each lamp socket until you find where you no longer have power. Since they are separate wire runs, I'd spend more time at the hitch/connector end.

[GABassin]

Thanks for the replies. I am attempting to get a voltage tester to check conductivity on all wires. Is there a particlar pin on the 4 pin connector that controls only running lights?

[Crowcommander]

If you have a late model Gmc or Chevy vehicle you may have a seperate fuse blown marked "trailer runnung lights" in your fuse panel,on the drivers side dash. Its there for safety in case your trailer wires fail,you'll still have lights on your vehicle. Mine went out and I found the problem on my boat trailer. They welded bolts in the trailer channel for the wires to run thru and they vibrated thru the insulation. Hope this helps.Crowcommander

[GABassin]

Yeah I have a 2002 ford and cannot find a fuse that has anything to do with the trailer running lights. Thanks for the input.

[BigBassGuy]

Is there a particlar pin on the 4 pin connector that controls only running lights?

Brown wire.

[BigBassGuy]

Did you check to see if you have a good ground going from the truck to the trailer? Alot of people overlook this part or think that because the trailer is hooked up to the vehicle everything is good. A little bit of corrosion will create a big headache. To test this, run a jumper wire from a clean spot on the frame of the truck to a clean spot on the frame of the trailer and see if everything is working properly.

[GABassin]

Ok now I feel like a real turd knocker. I looked at the fuses the other morning and they appeared be good. I guess through the frustration of me not getting to the lake at "prime time" I overlooked a fuse. I found the trailer tow backup/parking fuse blown. Hooked the trailer up and let there be light. Thank you very much for everyones help. Next time I shoudl double check and post afterwards.

[Dad_Golf_Fish]

The preview just saved me! I had a novel typed up, and when I went to preview for silly spelling mistakes (there may still be some) I see that the problem is solved. Oh well, I still give myself an "A" for effort.

If it makes you feel any better, I'm in the same boat (no pun intended). My left turn signal is out. The entire light had gone out, and I just pulled the burned out bulb and had to go to three auto stores to find the right one. I replaced it, and then I had a very bright parking light, but no turn signal. When I went to the right side, it had a different bulb. I just picked that one up today, and now the parking light and brake light work, but still no turn signal. My turn to break out the meter and start working my way through.

[cpmed]

I have a 1999 F-250, It has a fuse box under the steering wheel in the dash, and a fuse box under the hood drivers side that has the fuses for all trailer lights in it. 3 separate fuses for trailer left side lights, right side lights,and running lights. 2- 7.5 amp & 1- 20 amp. If you have a factory installed round plug thats the trailer fuses.

[luger306]

had the same thing happen check your ground I chased it for half a day a friend told me to drive around the block then everthing worked

[Don B]

I have a 1999 F-250, It has a fuse box under the steering wheel in the dash, and a fuse box under the hood drivers side that has the fuses for all trailer lights in it. 3 separate fuses for trailer left side lights, right side lights,and running lights. 2- 7.5 amp & 1- 20 amp. If you have a factory installed round plug thats the trailer fuses.

Lot of people don't know that. My Silverado has the same set up.

The only other thing I could add to the post is that most times, fuses don't blow for no reason. I'd bet your brown wire has rubbed some wee little bare spot somewhere that made it short and blow the fuse. That happened to me once. I fished all new wires through and found the spot after closely inspecting the wires I removed.

[egolfer]

On the same topic of trailer lights.  Over the weekend I replaced my burnt out driver's side break light/turn signal.  When I pulled out of the driveway everything was working.  When I stopped at the gas station, I noticed the turn signals were not working.  I jiggled the wire, literally with one finger and ALL the trailer lights went out  

I went around the trailer and reconnected all the lights and splices to my rear and running lights.  Now, only the break lights, turn signals, and emergency flashers work.  The rear lights will not run when they are on and no running lights work.  

I checked all the fuses in my GMC Trailerblazer and they are good.  Is it possible that the adapter from my truck to the boat has blown?  Any suggestions??