Check the C3, C16 timing cap for being installed backwards AND try a new timing cap 1 means relay is capable of pulling in 2 means no external current sense input is causing the pa3004 chip to drop the relay out 3 grounding pin 4 means no DC voltage input from the amps is causing the pa3004 chip to drop the relay out That leaves watching the voltages at these pins as the relay merrily cycles in and out: pin 1 at 12.7v stable? pins 4 and 5 grounded and stable? pin 6 at -7v stable? pin 7 at xx ac volts stable? and watch pin 3 go from near 0v when the relay is dropped out to 0.7v when relay is supposed to be pulling in.