Yes I know how to read the wiring diagram and thank you that would be really helpful

 

Here’s the power supply portion of the wiring diagram. The section I circled on the right runs to the rear junction block.

The wires on the left are the control circuits from the BCM - they break down as follows according to the numbers:

1 - Park lamp relay
2 - RR stop/turn
3 - LR stop/turn
4 - 3rd brake light
5 - Run/crank relay
6 to 9 - Data circuits for TCC brake to ECM, TCM and PTO depending on options

 

Did you get this figured out?

 

Ya i got it figured out it was the fuse box its was real dirty and corroded on the inside so i replaced it but thank you for taking the time to help me out

 

Good to know. I’ve only seen a couple of them have similar issues so it’s easy to overlook them as the cause. Glad you got it figured out.

 

just out of curiosity, was it a flood damaged vehicle? was the fuse box lid missing?

 

The box cover was missing

 

not the first time hearing that story. It has a lid for a reason.