Greetings,

I have a 1996 Ford F-250 XLT stretch cab, with a 460 c.i. (7.5 L) and auto transmission. It has the factory towing/camper package and the factory off road package installed. I'm the original owner so I know nothing has been altered.

It has the 7-wire trailer plug, and a 4-wire adapter. All factory.

For some reason the wire to the trailer plug, that sends power to the tail lights, quit working. Everything else (turn signals and brake lights) works fine but when I put a test light to the wire supplying power to the tail lights, I get nothing.

I checked the fuses under the dash and nothing is blown. I looked at the wiring under the truck, and nothing looks disturbed. Looks just like it did the day it came from the factory. Nothing's been damaged, nothing ripped or torn out. Everything is still in factory harnesses.
And the tail lights in the truck work fine.

Could there be another fuse inline? Or something else I can look for? It worked at one time.
There is absolutely nothing in my Chilton's or Haynes manuals about factory trailer plug wiring. They have wiring diagrams of everything else but not the plug. If I could find a wiring diagram it would be helpful.

Hope I didn't confuse everyone with my feeble attempt to discribe the problem! LOL

Thanks,
Bill

 

If I can recall correctly, there are still some round looking connectors under the rear bumper that hook back up to the trailer plug... possible corrosion between connectors, sometimes the back of connectors have corrosion as well. Pin point front of plug to behind it using ohmmeter to make sure the connector is still intact and not faulty itself. Tail light wire color code is brown.... worst case scenario splice a new wire to tail light wire. I'm providing wiring schematic but this is a very basic easy fix.https://docs.google.com/file/d/0B_fy...it?usp=sharing

 

Okay, I see those. I'll do that check. Thanks.
And, you're right, a jumper wire spliced inline might be the fix right now if this is the reason. Driving across country in a couple days and am quickly running out of time.

Thanks again.

 

no problem!! Update if possible, could very well help another with similar issues. Good luck and have a safe trip!

 

It could be possibly a dirty connection at the marker light relay, or even a faulty relay...

 

Found the problem. It was fuse "D" in the chart above. I didn't even know there was a fuse box under the hood.
Thanks everyone for your help!!

 

lol...wtg Idsubgun! At least it was an even easier fix than expected!