Radiator Fan Switch

[rambo82]

could somebody please tell me how to test the radiator fans?? they dont work at all.

I understand that you can test in the radiator switch some how. can anybody help me

[Rockabill]

Hi,

I too wanted to do this when I was having a problem with our '04 1.9Tdi overheating. The Haynes wiring diagram (their is a disclaimer at the beginning of the chapter saying it is 'representative') shows the power supply from Fuse F18 to the thermo switch as red (connection no.2 on the switch), and the outputs as Red (connection no.3) and Red/White (connection no.1). The connector numbers are very hard to see unless you have the thermo switch removed. On our Gal the thermo switch is on the drivers side of the radiator about a third of the way down. To test test the fans I bypased the switch and connected the red cable from F18 to either of the other 2 cables on the switch. With one of the cables both fans come on and with the other just one of the fans work. When I checked this out and found both fans to be working, I thought the thermo switch was broken. I replaced the thermo switch but still over heating. Turned out to be a loose impeller on the water pump, and therefore a lack of flow/heat through the radiator to activate the thermo switch. Even though the top connection rad pipe felt hot, checking the bottom radiator pipe it was found to be cold/warm.

Rockabill

[xavier]

Hi can anyone confirm the correct torque for tightening said rad fan switch, I've followed the figure mr haynes gives then realised it's for a petrol rather than the TDI. The sensor is still weeping despite me nipping it up a few times. Sensor was new as is the copper washer.