Hot Light Diagnosis (C Body)
NOTE:
These checks assume vehicle is not overheating. Verify proper operation of cooling system prior to diagnosing hot light.
Hot light is powered by a 15 or 20-amp fuse No. 6 (depending upon instrument cluster option). Light will turn on when PCM provides a ground for the circuit. If circuit grounds between light and PCM, light will illuminate any time the ignition is turned on.
- Turn ignition on with engine off (bulb test position). If hot light illuminates, go to step 3. If hot light does not illuminate, check the following:
- 15 or 20-amp fuse No. 6 in I.P. fuse panel
- Faulty instrument cluster bulb
- Open circuit between fuse and hot light
- Backprobe terminal GC7 at PCM with a test light to battery voltage. Turn ignition on. If test light does not illuminate, PCM terminal connection is bad or PCM is faulty. If test light illuminates, turn ignition off. Disconnect ECM connectors. Jumper terminal GC7 to ground. Turn ignition on. If hot light does not illuminate, check for open circuit between hot light and PCM. If light does not illuminate and all circuits are intact and power is available to light, instrument cluster must be replaced.
- Start engine. If test light goes off, no problem is evident. See DIAGNOSTIC AIDS. If test light is on, turn ignition off. Disconnect PCM connector. Probe ECM harness terminal GC7 with a test light to battery voltage. If light is off, replace PCM. If light is on, repair short to ground in circuit No. 1268. If no short is present, replace instrument cluster.
NOTE: Test numbers refer to test numbers on diagnostic chart.
- This determines which circuit is out of specification. All circuits except GD16 and GD15 should have battery voltage with ignition on, engine not running and ALDL test terminal not grounded.