On my '87 Pace w/454 chevy, the solenoids would only click when you turn the main/aux switches on or off. Since the motor starts, the main solenoid is on. With both switches on, check the voltage going into and out of the solenoids. If there is power coming out of them, then it might be the ground on your aux batteries. If there is no power coming out of one of the solenoids, up a jumper across the two large posts on either side, and check your output. Eddie Elk.
1998 Pace Arrow Vision 36' w/460, '03 Honda CRV, FMCA #388823, Gateway Getaways RV Club