06 F450 Wiring Issue

[Bobus]

So just aquired a 06 F450 Crewcab 6.0l 6spd. Truck didn't have a bed on it when I got it. I noticed that when you press the brake pedal the interior lights (dome lights) would come on. OK I figured it was because of the cut rear wire harness. Well got the new bed on, and if I open the doors, the brake lights come on. (Stay on maybe 30 seconds) Press the brake pedal dome lights come on. Everything else works as it should. Anyone have any ideas?

 

[turbom700]

There is a ground that goes to the frame right by the hitch. Alot of times those will get weathered away and cause such issue.

I just had this same issue with a 2001 Excursion. I ended up running a ground wire from the back to the front and ground it where the body ground is. Everything works fine now.

 

[Bobus]

Place to start looking..thanks

 

[zfaylor]

x2 on ground issue. Bad grounds cause some odd things to happen. The system will back feed and stuff will go haywire.

 

[Bobus]

Found the issue today, more by accident while running wires for a strobe light. Something either chewed on the wires or they chafed through behind the drivers kick panel. So the high mount brake wire was touching the dome light wire.

 

[Mo Smoke]

By looking at the mud on the floor I would say chaffed.