"COAST" Circuit Test

Turn ignition on and connect voltmeter to Lt. Blue Black wire and ground. Depress "ON" switch in steering wheel and hold down on "COAST" button. Voltmeter should read approximately 1.5 volts on Ford, Mercury, Fairmont, Zephyr, Mustang and Capri, 6 volts on all other models. If all functions check good, perform SERVO TEST  and SENSOR TEST , and install a known good amplifier and recheck.