I have a 1998 F150 Ford Pickup with towing package. The left running light terminal in the plug is the only thing that works. All the other terminals are dead. Turn signal, stop light, etc. I have checked all fuses and they are good. I checked the fuse box under the hood also. The tail lights on pickup work fine it's just the towing package plug that doesn't. I checked the plug and no wires are loose on it. Have traced the wiring back to the front of the pickup to where they plug in - all seem to be together tight. Trailer brake controller indicator light lights up to show it is okay. Do you have any ideas what else I can do or check?

 

does your 4way plug work?

i would check over the brake controller wiring, since thats a non factory addition

 

I had a problem with my running lights not coming on. Turns out the running light terminal on my 4 pin connector had corroded and was no longer making a connection. Bought a new 4 pin and 7 pin setup from RockAuto for $15 and everything is working perfectly now.

 

When you say you checked the fuse box under the hood, did you check both the BJB ( Battery Junction Box ) and the Engine Mini Fuse panel ?

The mini fuse panel was not documented in the 1998 Owners Manual for some reason.

This is the page from the 1997 owners manual


This is for the L & R stop / turn lamps.

When you are testing the trailer tow battery charge pin, do you have the key in the run position ( this is off in any other key position ) ?

How are you checking the fuses ?

 

Thank you SSCULLY, that fixed the problem, the mini fuse was blown. The engine mini fuse panel on our 98 is located on the drivers side on the fender wall under the hood back towards the cab and is hard to see. Thank you for your help.

We checked the fuses with a continuity tester, visual and a test light.