I am chasing an electrical issue with my 97 F-350. The rear lights have not worked properly in the several months that I have owned the truck. This weekend I took the flatbed off to fix it, and thought that I wouldtry to figure out the wiring problem.

My problem is that when I turn on the left turn signal, I get 12 volt on that wire and 8 volts on the wire for the right turn signal. It is the same for the right turn signal, 12volts on the right wire and 8 volts on the left wire.
The front signals do not have this issue, it is only with the rear of the truck. There is also a group of wires running to the rear of the truck for a trailer plug that appear to be factory wires. These wires mimic the same behavior as the wire for the truck lights.

Can anybody help shed some light on my situation?
Thanks,
Bill

 

Does it have LED lights on it ?

 

No, it does not have any lights on it. The bed is sitting on a metal stand beside the truck.

Bill

 

Could be quite normal. PCM put out a voltage, through a pull up resistor, to monitor rear brake - turn signal functionality.

What is the original problem causing you to troubleshoot?

 

Here is a link describing the situation and why it does it ...

http://www.google.com/url?sa=t&rct=j...73612305,d.aWw

I would just attach the PDF however don't know how to do that.

 

The reason I removed the bed was that it must have lived it previous life in a Salt mine. It was very rust to the point that I didnt trust hooking a trailer to it. I have new CM flatbed waiting to go on the truck as soon as I get the frame rails painted.

Prior to removing the bed you could notice a faint hint of the opposite turn signal trying to illuminate when using the other sides turn light.

Your post makes he hopefull that it could be a small issue with grounding.

Bill

 

Rather than attach the PDF, post the direct (no CIA-gle) link to it: https://www.ford-trucks.com/forums/a...chmentid=49079

FIRST thing to check is the center stop light in the cab roof.

 

The center stop light was the culprit. Thank you very much.

Bill