I have a bit of electrical work to do on my newly purchased 90' 240 Wagon. All the wires running back through the tailgate hinges have been slice. In checking the wire I have discovered that all but one of the wires have no power running through them? I checked the fuses, which look okay yet the lead running off the fuse box aren't showing any juice either? Am I missing something? Could it be a bad relay?

 

You have to get a good wiring diagram and trace backwards to a point where you're supposed to get 12 VDC (ignition "On," not "Start"). From that point, also do a continuity test (beep from a digital multimeter, diode setting) from that point back to the tailgate-meaning if your wiring is fine, you should hear a beep. You probably have a break at some point in the wiring or a faulty relay.