I have a 2003 f250 with a 6.0. i don,t have instrument panel lights, tail lights, or power to the trailer hookup. i think it all started when i was pulling a travel trailer and after awhile i noticed i didn,t have trailer brakes anymore. i have checked all the fuses and can,t find one thats blowed. any help will be appreciated

 

Did you check for blown fuses or a bad relay under the hood? Drivers Side.

 

yes, i looked at the fuses and they were good. how do you test the relays? do you know which ones are for the tail lights, dash lights, trailer lights and brakes?

 

In your user manual in the back is a list of the fuses, relays and where they are located, the relays that are identical you can just swap out to tell if the right one is okay.

 

A 2003 doesn't have Power Distribution Box under the hood. 2002-2004 trucks were odd that way. There is one fuse (totally undescribed as far as I can tell), the PCM relay, a couple of trailer tow relays and the 4x4 shift relays, all in different small boxes.

Did the OP check his fuses with a meter or a test light? Fuses will often fail and not appear so visually.

 

I have a 2003 and it does have a Power Distribution Box under the hood with fuses and relays in it.

 

Hmm. There is no mention of it in the Owner's Manual available online. So I assumed it didn't have one. I've been wrong before.

 

ok, i just went out and checked every fuse, every maxi fuse, and every relay with a ohm meter and they all checked out ok. i also checked under the hood, those 2 small power boxes on the drivers side which consist of 2 mini fuses and some relays. they all checked out good. like i said i,m not getting power to the tail lights, dash lights, and trailer stuff. just can,t find out the circuit their all on

 

Ok so no running lights and no instrument lights. That makes me wonder if you don't have a bad headlight switch.

Do you have headlights?
Do you have the autolamp feature?

If your headlights work, then you're most likely getting power to the switch.

If you have the autolamps option, I would select that and cover the sensor in the front of the dash and see if the lights come on with the autolamps.

Looking at the diagram below, I'd make sure I had incoming power at pin 10. Then I'd make sure I had power going out at pin 14, with the connector connected.

 

yes i,ve got head lights, brake lights and signal lights. i don,t know if i,ve got that autolamp feature or not, i,ve never used it. and i get no power at all to the trailer hookup

 

Test the switch like I mentioned. If you have autolamps, you will have a small A position to the left of OFF on the light switch, and an ambient light sensor on the inside drivers side edge of the defrost vent above the dash. Turn the light switch to A and cover the sensor with something.

 

I don,t have the autolamps feature, and the headlights work.

 

OK so now it's time to pull out your headlight switch and start checking the pins with a volt meter or test light.

 

no power at pin 10, and no power at pin 12 when it,s connected. it,s got to be a fuse right?

 

Keep in mind that my wiring diagrams are for a 2004. I think they are the same as a 2003.

Pin 10 goes directly to the Central Junction Box, connector C270b, 15 amp fuse #17. There are no relays or anything in between.

No power on pin 10 is definitely your problem.

If you're 100% sure that fuse 17 is good, check the fuse contacts and make sure they are clean and tight, then remove the CJB and check for corrosion at the connectors in the back.