Have RV Questions? Ask an RV Mechanic Online.
Do I understand that you hooked this up to another truck and all the lights don't work either? Do the turn signals work? Do the electric brakes all work?
Do I understand you tried this on two vehicles? MOST of the time, when the lights AND turn signals won't work the problem is a bad ground lead in the cord or plug or it may have come loose at the connection. IF the brakes work, then that probably isn't the case, which is why I asked if they work. When the cord is hooked up and you apply the brakes you should hear them "hum" some or click as they are applied. It takes a person working the pedal so you can do this. Can you try this and get back to me?