I have a Mk3 K plate Golf 1.8 cl, the engine is overheating in traffic but not when driving normally.I noticed that water was bubbling out of the expansion tank and also that my cooling fan was not cutting in.I checked the thermo switch by bridging the contacts i.e 1 and 2 and 1 and 3 which correspond to low and high fan speed but fan did not cut in which proved the thermo switch was okay, next I connected the fan directly to the battery on both high and low speed connections the fan worked okay. Next I got a meter and checked that I was getting 12 volts at the thermo switch which I was, I then with the contacts bridged on the thermo switch checked the voltage at the fan plug and 12 volts received okay, as suggested in an email on this forum I changed the expansion tank cap which has stopped the bubbling (both top and bottom hoses getting hot) but fan still does not cut in. While the car was in overheat mode I checked the output voltage from thermo switch and to cooling fan plug which was 12v + but still fan refuses to operate.
I am at a complete loss why the fan does not operate as I get 12 volts to the fan can anyone help me please.
Regards
Raylo