Posted by Tim Holloway on Monday, April 12, 2004 at 6:53PM :
Ok, here is one for you trailer wiring Gurus; I made several modifications to my new split deck hauler. The biggest was to rewire the entire trailer. A good friend is the service manager at a local tractor trailer shop. He gave me a big box of semi trailer wiring harnesses, lights, and misc. components. The system is a main 7 wire harness which has a flat plug at one end. This plugs into a junction block which will receive 7 other harnesses to perform other tasks, for instance, the marker light harness has the same 7 position plug but with only 2 wires contacting in the junction block (1 power, 1 ground) There are 2 harnesses for the brakes. One would have worked but there were 2 in the pile and I wanted to fill all of the spots in the junction block to keep out moisture so I wired one to the front axle and one to the rear axle. I figure if one fails I wont lose brakes on both axles. Thats the background, here is the problem:
Before installing the trailer plug I put 12 volts to the different wires in the main cable. All of the lights operated properly and the brakes hummed. The brakeaway switch operated properly when the key was pulled out. I installed the plug, exactly as before (the brakes were functioning properly before undertaking this) Now when connected to the truck, the lights all work properly but not the brakes. I have a Tekonsha Prodigy controller. It is flashing a message"S.H" which means "Prodigy detects a brake wire shortduring idle condition" When I apply the brake pedal the message changes to "O.L" which means " Prodigy sees an overload condition during operation" I ran out of time to play with it so I thought I would bounce it off you guys.
Thanks for your patience reading this novella
Tim
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