Radiator Cooling Fan Temperature Sensor / Switch: Testing and Inspection

AFTER-RUN COOLANT THERMAL SWITCH/ENGINE COOLANT TEMPERATURE SENSOR, CHECKING:

Special Tools, Testers And Auxiliary Items:
^ VW 1594 Adaptor kit
^ VAG 1527B Voltage Tester
^ Fluke 83 multimeter
^ Wiring diagram

Test Sequence:
- Disconnect 4-pin harness connector from After-run Coolant thermal switch F95/G2 -yellow-.



- Bridge connector terminals -1- (grey) and -4- (brown/green) using jumper wires from VW 1594 adaptor kit.

^ After-run coolant pump must run.

If pump does not run:




- Disconnect 2-pin harness connector from After-run coolant pump -1- and connect VAG 1527B tester between connector terminals using jumper wires from VW 1594 adaptor kit.
^ LED must light up.

If LED lights up, Voltage supply OK.

- Replace After-run coolant pump V51.

If LED does not light up:

- Locate and correct open circuit using Wiring diagram See Wiring Diagrams.

Thermal switch resistance, checking:



- Connect multimeter between Thermal switch connector -B- terminals -1- and -4- using VW 1594 adaptor kit and measure resistance:

^ Specifications:

below approx. 103 °C = infinite ohms
above approx. 104 °C = 0 ohms

If specifications not obtained

- Replace switch/sensor F95/G2