Exhaust System Temperature Indicator: Testing and Inspection

FAULT DIAGNOSIS HINTS
When current (+15 circuit) is applied to pin 4 of the relay, the warning lamp is grounded and lights up for about 3 seconds. If it remains alight, there is a break in the thermostat circuit. Normally, the warning lamp will go out and stay out until the temperature exceeds the preset limit.
1. Also check that fuse 17 is intact and that current is supplied to the temperature sensor and the relay.
2. Also check the connectors, wiring harness and ground connections.