On the road, running lights keep blowing.

[Gmhorse]

Hi guys. New to the forum here. Sorry not to use the search function, but I am on the road and only have my phone for access. My running lights keep blowing the fuse in my truck. Same trailer I have had for years and no additions to wiring etc. Any suggestions on where to look first? Simple things I can check on the road. Any help would be appreciated to get me going again. Brake lights and turn signals work fine.

[msp2jxr]

If you know where your junction box is located, that would be the first place I would start. Check for wires that may have come loose from the wire-nuts which could be shorting against the box. I have experienced this once myself.

[Gmhorse]

Thanks for the quick reply. I did check the junction box, and everything seemed ok. Both of the bulbs in the tails lights had a white chalky corrosion. I used a piece of sandpaper to clean them, and it seems to have done the trick. Fingers crossed.

[cpaulsen]

When you clean your bulbs.put a little dialeltric grease on the keep the corrosion down.

[KenBob]

Check all the bulbs on the circuit for clean connections.

Check the 7 way connector for clean and tight connections. Poor connections cause high resistance and blown fuses. Same trailer for years. Same connector for years.

[gkainz]

what truck? My 2nd gen Dodge (97) has a trailer lights relay in the PDC under the hood. Dealer did not wire the trailer lights thru that - they tapped into the truck tail lights. I rewired it thru the relay. But, the warning from Dodge literature was it would overload and smoke the headlight switch rather than what you're seeing with blowing fuses. Did they work before and now failing? If so, like noted above, check all the fixtures for corrosion, clean bulbs and apply dielectric grease.