I've developed an electrical issue in my 85 F350 6.9 diesel. Someone powered an electric fuel pump off a red wire with yellow slash marks; this wire protrudes through the fire wall on the left side with the main harness. It travels in conjunction with two other wires (red with white dash and black) and terminates in an unused connector.

I have read some caveats online about powering a fuel pump directly from trigger voltage and will rewire the pump to a relay when my problem is solved. The problem is intermittant and seems to be related to movement in the gear shift or transmission linkage. When I down shift, the problem occurs or goes away.

Lack of power to the red/yellow slash wire affects the fuel shut off solenoid as well. I needed a quick fix and wired the pump directly off the battery through a manual switch but had to jumper power to the red/yellow slash wire before it would start.

When I energize the remote switch with the key switch "off", not only does the fuel pump start to run, but also the dash lights and buzzer cycle (seat belt warning and brake).

If someone has any ideas re what I am dealing with, I'd appreciate the advice. If anyone knows where I can purchase a high quality reprint of an electrical and vacuum manual please direct me there. Thanks.