Coolant Temperature Gauge and Warning Symbol, Checking

Coolant temperature gauge
Electronic Engine Coolant Temperature (ECT) thermal switch -F76-, terminal identification





+ - Voltage supply
C - Coolant overheat warning symbol control (Auto-Check system)
R - A/C compressor cut off (overheat)
T - Coolant temperature gauge control

Thermal switch located on coolant pipe behind right cylinder head.
- Remove thermal switch connector.





- Connect instrument/gauge tester VW 1301 to terminal T of thermal switch connector.
- Set tester VW 1301 to 560.





- Switch ignition ON.
- Coolant temperature gauge needle must lie within tolerance range (arrows -A-)
- Set VW 1301 to 58.
- Coolant temperature gauge needle must lie within tolerance range (arrows -B-).

If NOT:
- Check wiring for open circuit according to wiring diagram, repair as necessary.
- Check voltage stabilizer.

If OK:
- Replace coolant temperature gauge.

Coolant overheat warning symbol (in Auto-Check system)

- Remove electronic thermal switch connector.
Thermal switch located on coolant pipe behind right cylinder head





- Using a jumper wire, connect terminal C of thermal switch connector to ground.
- Start engine.
- Warning symbol must be displayed after approx. 30 seconds (warning chime sounds)

If NOT:
- Check wiring for open circuit according to wiring diagram, repair as necessary.

If wiring checks OK:
- Replace printed circuit board in instrument cluster.