Drive Circuit Test

To verify drive circuit is operational, turn ignition off. Disconnect component connector. Turn ignition on, and ground ALDL test terminal "B". Probe drive circuit terminal of harness using a test light connected to battery voltage. If test light does not glow, backprobe appropriate terminal at ECM connector. If test light now glows, repair open in circuit between ECM connector and component harness connector. If test light does not glow, problem is faulty ECM connection or faulty ECM.