The defrost coil is only getting around 20V in defrost cycle on an old GE fridge. I have replaced the thermostat, and tested both the coil and the timer for continuity; both passed. When I jump 3 & 4 on the harnes to the timer, the fans run. I put a 12g wire accross 2 & 3, and the heater coil still did not heat up. What else should I try?