No Running light or 12 Volt Power on 7-Way Connectors for 2004 and 2006 Ford F-250

Question:

2004 and 2006 f250 trucks have no power for running or 12v at plug in. Power is all working at square pin plug on truck. Fuses all good. Replacment of wire from truck to plug in also no help. All other outlets on plug work and trailer has turn stop brakes. What are we over looking?

asked by: DANICA N

Expert Reply:

There could be a relay or relays that are bad or missing on your 2004 and 2006 Ford F-250 trucks. On the 2004 make sure the fuse in location 38 is good, it is for trailer tow parking lamps. Location 115 is the fuse for the 12 volt circuit and location 305 is the 12 volt circuit relay.

On the 2006 location 38 is trailer tow parking lamps. Location 107 is for the 12 volt circuit, and location 301 is the 12 volt circuit relay.

If you are testing for power at the connector under and a little further forward on the truck frame and it is working there but not at the 7-Way then problem is in that harness. If you just replaced the wire the problem could be damaged or corroded pins in the connectors. Using a small wire brush to clean out corrosion will help. Then use dielectric grease # LT37534 between the connections to repel moisture and resist corrosion.

Also make sure the pins on the 7-Way connector as well as the trailer side connector are clean and free of corrosion as well.

expert reply by: Michael H