What would cause my truck (03- f350 6.0 diesel) to have no brake lights, signal lights, 4 way flashers or back up lights but have all the running lights work?. I have checked and replaced every fuse and bulb, the 4 way/signal flasher, multi function wiper switch. I removed the entire fuse panel, cleaned all the contacts and made sure all the rear connections were well seated. Still nothing!!!. Is the actual fuse panel bad??. Is there a common circuit that all of these run through that could be bad in the panel?. I'm at a real loss here and would really appreciate some help. Thanks

 

 

Every light you described comes from the steering column. Except for back up lights I would be looking at the turn signal switch.

 

I listed that in my post. This I why im lost. I have done a pile of googling on this and searched old threads. I'm not out to waste anybodys time. I checked and replaced every bulb, fuse, the 4 way signal flasher, the turn signal switch, pulled and cleaned the whole fuse panel. Unless there is a broken connection in the fuse panel itself??. This is why I was asking for help. The signal lights, 4 way flashers, back up lights and brake do not work but every running light on the truck does. I was hoping maybe someone with an answer would step in a say yup(.....) is you problem. Any help is appreciated. I have done every fuse, bulb and the flasher reply as well as the multi function switch already

 

 

Could the problem be a Relay?

One more thing, but you probably would've noticed.. Check and look around for critter damage to wiring harnesses.

 

Pick the easiest circuit to trace, and start troubleshhoting it with a meter. I think brake lights would be easiest.

Start at a midpoint in the circuit, such as the brake light switch, and verify voltage when the circuit is activated. If there is, work towards the lights. If there isn't, work towards the power source.

 

That's exactly what I did many years ago on a Volvo and ended up back at the relay. I had already replaced the same relay so I didn't think it was the culprit, but the replacement was bad.

After installing a good relay, everything worked.,

Sorta the same thing happened when my 4x4 would not kick in. I replaced the relay with new from Ford and that did not fix it. The problem was the 4x4 switch on the dash.

 

OK...Riddle me this Batman!!. Its fixed but I don't understand how. I pulled out the schematics and a tester. Re-checked the brake light switch...yup, checks out good. Keep googling again.....check wiring plug connections along the frame a they sometimes get corroded. Wedge the brake pedal to see if I have continuity(sp?) at this wiring plug/junction....nope, nothing. work my way back to the plugs that are under the hood just outside the firewall before they shoot down along the frame. Pull them apart, check again for continuity with the brake pedal pressed....again nothing. Back under the dash. Follow the light green wire (following the schematic, it tells me it goes into the multi-function switch))Chase the light green wire up to the wiper/signal multi-function switch unplug it to test....yup! I get the light to shine!. Read the schematic some more and follow the white/red stripe and light blue wire out of the multi switch to the 4 way flasher.....Nothing. Google some more about testing that there is power from the light blue and white/red stripe wires on the back of the 4 way flasher back to the switch. Stab the light blue wire ....nothing. Stab the white/red stripe ...SHAZAM!!!!!....the flasher and 4 way signal lights on the truck flash up and start working!!!!. I do the happy dance and cheer!! although I don't understang why by stabbing the wire with the tester now has everything working???. Stomp the brake pedal....I have brake lights!!!!! Signal lights now work too!...Yahooooo!!....Sooooo.....what the hell just happened???

 

You tortured the wire harness into functioning again?

 

Loose firewall connector, maybe you or prior owner had body off engine work done to your 6L.
In putting it all back together something didn't get fully connected and wiggled loose over time..

Just an example of how weird stuff happens.

 

Yep.. Sure sounds like a loose connector or just a bad seat. Something was not seated correctly or loose.