Tail light 10amp fuse has no power

Chasing a power is issue the 10 amp fuse in fuse box doesn't have any power. It runs the tail lights. Running lights and tail lights don't come on

 

TAIL fuse will only have power with the Tail lights switched on.

What year is your truck?

 

2008
Fuse inside the truck doesn't have power. Checked all of them under hood. Seen nothing bad. Checked with power probe. Was working on a trailer yesterday and tried lights that's when all the tail lights went off.

 

So nothing on either side of the fuse with the tail lights turned on?

Did you try powering up the fuse with the power probe?

The TAIL Fuse (10A) is powered by the TAIL Relay which is controlled by the Body ECU and powered by the J/B Fuse (50A).

 

Nothing on either side of fuse. Sent power on bottom side of fuse lights came on.
Check all bulbs and nothing was bad. Just confused why there is no power coming to fuse.

 

So it would seem either the TAIL Relay failed or the Body ECU isn't turning it on for some reason, have to go there to test further or try swapping the relay first.

The TAIL Relay is located on the back of the Driver's Side Fuse/Junction Box/Body ECU
The relay has Power at all times on Pins 1 & 3, the Body ECU Grounds Pin 2 to turn the relay on. Pin 5 is Power out to the TAIL Fuse (10A).

 

I ll try this tomorrow. If no success then it has to be the body ecu then ?

 

Well you also need to check the input to the Body ECU from the Combination Switch, the switch Grounds Pin 13 (Green) of Connector B5 at the Body ECU to signal it to turn on the TAIL Relay when the switch is in the Tail light or Headlight positions.

Also verify the ECU-B (7.5A) and IG1 No 2 (10A) fuses are good but if your headlights work and there are no other issues I suspect they are.

 

Usually, one can troubleshoot lighting issues with a wiring diagram if multiple lights are involved.

 

Diagram is attached in the post above, only a few possibilities since we have no power at the TAIL Fuse.

 

Sorry this took awhile but I've found my issue. Notice the 10amp fuse and 7.5 amp had some discoloration on them. Like something got hot. Found another fuse box installed it and everything is back to normal.
Thanks everyone for the help