Ok, I've pulled that. Still blows the fuse if I jumper #6 & #7.
I pulled the 15 pin bulkhead connector from the firewall that has the Black/pink wire. It shows continuity from there to the 5 pin connector at the rear of the truck.
I wired the backup lights directly to the positive side of the battery. I have 12.5 volts at the 5 pin connector at the rear. So I know the wiring is ok there.

Could there be a problem in the ignition switch?

I checked for continuity between the 5 pin connector at the rear to the steering column and it's good.

What I don't understand is why #6 and #7 blow fuse E when jumpered. I literally can't find a short in all the wiring.

 

Ok...
So I have the 15 pin bulkhead connector disconnected. Fuse E still blows when I jumper 6 and 7 on the TR sensor.

 

What is #6 and #7 jumpered?

 

TR sensor plug.
#6 Black/pink (backup lights)
#7 Purple/orange (Hot in Run)

Edit: I do NOT have the TR Sensor connected. I'm just working with the TR plug without the sensor.

 

I forgot to mention that if I have the TR sensor plugged in and I rotate the position from Neutral to Park, the backup lights never come on.

 

I connected the TR sensor and checked pins 6 and 7. I have 12 volts on both.

If I rotate the TR sensor into Reverse, the fuse blows.

 

Next question, where do you find a "15 pin bulkhead connector"?
You should have two bulkhead connectors a C202 (76 pin connector) and a C205 (24 pin connector).

 

It the C205 connector. There are only 15 pins used out of the 24. Sorry for the confusion.

I connected the TR sensor, with Reverse selected, I have continuity. Its showing good with no high resistance. As soon as I apply power and turn the key on, it blows the fuse but only with Reverse selected.

 

Do you have Auto day & night mirrors?

 

Yes, just the windshield rearview mirror.

 

FOUND A PROBLEM!!!!

 

Subford, that was the problem!!!!

I separated the wires and I have backup lights and the fuse hasn't blown again!!

Wow!! It's awesome that it's working again!!

Thanks again for your patience and your quick replies!! I've been banging my head against a wall the last week.

 

Could you back off a little and take that photo again?

 

Yes. But I don't know how well the pics will look.
All 3 wires were melted corroded through.

I took 2 more.
One shows the damaged wires and the other shows the scorch mark on the sheet metal.
​​​​​​