[Bobboloo]

Check the ground as Kurt mentioned and also check the multipin connector where the harness goes through the frame. I suspect this is where the problem is. Unplug the connector spray some tuner cleaner in the connector and plug and unplug a couple of times to clean the connector and then reconnect.

You can pickup tuner cleaner at any Radio Shack. It's basically contact cleaner for electrical parts.

Bobby