Engine Coolant Level Switch
- If DTC 72 is present, diagnose trouble code first. Ensure coolant reservoir tank is full. Turn ignition on, with engine off. Coolant level light should illuminate and then turn off. If coolant level light turns off, go to next step. If coolant level light does not turn off, go to step 5).
- Drain coolant from reservoir tank. Coolant level light should come back on. If light did not come on, disconnect coolant level switch harness connector. Connect DVOM between battery positive and coolant level switch harness connector Black wire terminal. See Fig 1 . Battery voltage should be present. If battery voltage is not present, check for open Black wire to ground. If battery voltage was present, go to next step.
- Check for battery voltage between ground and coolant level switch harness connector Yellow/Black wire terminal. See Fig 1 . If battery voltage is present, go to next step. If battery voltage is not present, check for open in Yellow/Black wire. If circuit is okay, check for faulty PCM connections or faulty PCM.
- Connect test light between ground and coolant level switch harness connector Yellow/Black wire terminal. If test light illuminates, check for short to battery voltage in Yellow/Black wire. If test light does not illuminate, replace coolant level switch.
- Disconnect coolant level switch harness connector. If coolant level light turn off, replace engine coolant level switch. If coolant level light did not turn off, connect test light between battery voltage and coolant level switch harness connector Yellow/Black wire terminal. If test illuminates, check for short to ground in Yellow/Black wire. If test light does not illuminate, go to next step.
- Install Tech 1 scan tester. If scan tester indicates LOW, replace faulty PCM. If scan tester does not indicate LOW, check for faulty instrument panel cluster.
NOTE:
Do not remove pressure cap from high fill reservoir while engine is at normal operating temperature.