hi iv got mk3 tdci 2001my problems started when bottom water hose split while driving temperature gauge went to red so opened the bonnet and notest radiator fans not on. RAC HOME.Changed hose coolant everything fine until today temperature went nearly to red so pulled over lifted bonnet with engine running and once again i noticed no fans working turned off for 10 mins went home fine iv tested fans with wire from battery and both work fine so i was wondering Howe can i test fan relays. heater works fine so i guess no thermostat problem.im not very good with electrics so need step by step guide .THANKES JOHN

hi guys and girls. surely someone on this site can tell me a way of testing relays.Or if anyone knows of another reason fans wont come on PLEASE TELL .hope someone can help thanks john

hi guys and girls. surely someone on this site can tell me a way of testing relays.Or if anyone knows of another reason fans wont come on PLEASE TELL .hope someone can help thanks john

Sorry John,cant tell you how to test relays electrically,but when they opperate you should hear a "click" from the fuse box / relay box,also the radiator fan has its own thermostatic switch in the wiring possibly close to the water temp sender or fixed onto / into the radiator which tells the relay to switch on the fan,sorry I cant help any further.

Kristal

The easiest way to check if the relay is faulty is to swap it with a similar one inside fuse/relay box.

It does sound like a relay fault, altough it may be worth finding the temperature sensor and use a wire to bridge the connection there, that would tell you whether the relay was a fault as the fans should start up if the relay is ok. If they do start then the fault is likely to be the temperature sensor.

Hope this may help

Pogo

sorry for delay getting back to you all. but computer probs.anyway i took a good hard look in fuse box and pulled out a yellow fuse 60 amp it looked all right but i took off see through cap and very carefully touched the fuse wire and it was broken.so i changed it the car now does not get hot enough to start the fans.i left car ticking over for 45min and gage was just under halve way.so still not sure if fans work but temperature all right.SO YOU MUST TAKE OF CAP TO SEE IF THISE FUSE IS GONE.!Removed! i said before there was no sign that it was gone just buy looking.hope this helps someone else AND A BIG THANKE YOU TO ALL THAT REPLIED THANKS JOHN