Hey all, I know there have been a number of threads on this issue and a number of members have been helpful to a lot of people but the fix has been sent in PM so I cant find it with my searching so sorry to create a new post.
Truck is 2004 F-250 Lariat 6.0 powerstroke with auto trans. Symptoms started as no dash lights and no tail lights, got the fix-it ticket and went on my way home, found fuse 17 to be blown and replaced with no change. started at rear of truck and tested all wires in c408 to the connector in the back of engine bay drivers side and found no shorts. could not find the next leg from there to inside of vehicle so started at the switch and have power out to vehicle security control module and again out from there on the brown wire but again loose the signal. I am making the assumption that where I loose both of these are at the trailer tow parking lamp relay internal to the fuse box that I have read about. If one of you would chime in on how I can bypass this or test it I would greatly appreciate it.

 

Okay so if you have verified all fuses, lightbulbs, and wiring and they all test good but you still have no running lights here is what I did.
1) Remove positive lead from drivers side battery.
2) Remove dash trim panel over fuse box if not already done.
3) Unbolt fuse box (CJB) 4 10mm bolts.
4) Locate black and grey harness on right side of the back. Pictures of what you are looking for below.
5) Locate brown wire in each, will be in the top row close to middle.
6) To test internal relay put a jumper wire across these while plugged in and turn light switch to auto or on position with the key on.
7) If you have running lights now you have confirmed that the relay is bad and you can purchase a replacement CJB or remove those wires from the harness and place them on an external relay.

 

I was able to get it fixed

 

HI CAN YOU HELP ME WITH THIS I FOLLOWED THESE STEPS FOUND BAD RELAY HOW DO i WIRE A NEW RELAY IN LINE I TRIED TO CONNECT A FUSE BETWEEN THOSE TWO WIRES AND I LOST MY TRAILER TAIL LIGHTSI AM GUESSING THOSE WIRES NEED TO REMAIN ATTACHED TO THE FUSE BOX. SOME HOW THE TRAILER LIGHTS NEED TO BE CONNECT TO THIS NEW RELAY. THANK YOU FOR YOUR HELP

 

Is yours the same Series/Year?

 

Yes it is 2004 f250 hd fx4

 

'Double check' that you still have 12v on gray connector (C270b) PIN 5 with the HL switch ON/PRK.
Bridging PIN 5 on the Gray connector , and PIN 3 on the Black connector (C270h) should illuminate the truck and trailer running lamps.
If power distribution is not on PIN 5, re check fuses.
It's always best to install a 'stand alone' relay as a fix, than an inline fuse because the fuses ahead of the CJB and components shouldn't carry the full loads of the truck and potential trailer illumination load/draw.

 

Thank you sir

 

Let me know if you need connector/pin views etc, or a drawing should you need to add in a external relay..

 

I will thank you