Quote Originally Posted by zeroasylum View Post
Car MK4 golf 1.6 litre engine code AVU

I have a quick fan question. So my fans work on the slow speed when the AC is on. They also work eventually on the slow speed when the engine heats up and VCDS shows relay one activated however they have never kicked in on the high speed even in traffic at when the daytime temperature was over 30 degrees C. Now I have looked at the manual but all the guides say to bridge pins 1 and 2 or 1 and 3 on the thermos switch (which is new) but my switch is the grey one with only 2 pins. So how do I test the fans to force relay one and 2 to activate. Also should the fans run after the engine switches off. They did when I first got the car but that was due to a faulty stuck open thermostat now replaced and just flattened the battery eventually. I think relay 2 could be fried but I need to test it before ordering a new fan controller module.

Thanks

Zeroasylum
The fans MAY run after the engine is switched off. Doesnt mean there's a problem if they don't. I can;t see the thermostat causing them to run on and flatten the battery. If it was open the car would run cold.

If it only has a 2 pin switch then there's no high speed.

TBH it all sounds normal from what you have written above.

Gavin