Common Symptoms
- Engine temperature warning light stays on continuously
- Engine temperature warning light does not illuminate when key is on
- Intermittent engine temperature warning light operation
- Check engine light illuminated with no actual overheating
- Warning light flickers or behaves erratically
Most Likely Root Causes
- Faulty instrument cluster or gauge assembly
- Damaged wiring harness between PCM and instrument cluster
- Corroded or loose connector at instrument cluster
- Failed PCM output driver circuit
- Short to ground or power in warning lamp circuit
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Component Location
The engine hot lamp circuit runs from the PCM to the instrument cluster warning light bulb or LED in the dashboard.
Manufacturer Notes
Some vehicles use multiplexed communication between the PCM and instrument cluster for warning lamp control rather than direct hardwired circuits.
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