RV Running lights

Your pigtail is going bad you need to replace it

while your replacing the piggie tail find the ground on the tt and take off and clean to bear metal. grounds are 99% of trailer light failure.

Or just clean the contacts. Last trip out I needed to clean the plug and socket connectors for exactly the same symptom.

I always squirt some WD40 into my trailer connector on the truck side. Wiggle it around some then lock in place... This just cleans the contacts - a good non-conducting grease is probably better but all of us RV'er will have a yank of wire, a roll of duct tape, and of course a can of WD-40...

To troubleshoot picking up one of these 7-way test plugs really is neat as this lets you know right away whether the trouble is on the truck or trailer side with the running lights... I got mine from AMAZON but I'm sure they can can be found at an auto parts store. ETRAILER.com would be another source...


Roy Ken

I always squirt some WD40 into my trailer connector on the truck side. Wiggle it around some then lock in place... This just cleans the contacts - a good non-conducting grease is probably better but all of us RV'er will have a yank of wire, a roll of duct tape, and of course a can of WD-40...

To troubleshoot picking up one of these 7-way test plugs really is neat as this lets you know right away whether the trouble is on the truck or trailer side with the running lights... I got mine from AMAZON but I'm sure they can can be found at an auto parts store. ETRAILER.com would be another source... Etrailer.com is also a good place to see some pin-outs and the have a great collection of how-to-do videos...


Roy Ken

Try some electrical spray cleaner and they apply some dielectric grease on the 7-way plug and outlet. CRC makes both of these and they're easy to find. I fixed my faulty multi-function switch on my truck among other things. It saved me some money.

Great, thanks everyone.