9 replies to this topic

[VincentL]

Morning gentlemen,

 

I've had an issue with my cooling fan not turning on. Things i've tested so far:

1. Letting car sit and idle until it's at 100C

2. Shorting the pins where the (K13) relay sits with clippers = Fan turns on

 

Should I switch out the big grey block as shown in this video?

 

Additionally, would changing the car horn relay for the fan relay and testing the horn be a way of testing the relay itself?

Bosch 0332209159

Edited by VincentL, 16 May 2024 - 05:48 AM.

[Ivor]

I believe the relays can be swapped, make sure it's the same type, I did this to eliminate relay with a different fault. Relays are common types and easily bought

[Ivor]

I'd test the relay first, they're only a few £ from a motor factor, always handy to have a spare anyway

[F757lkk@gmail.com]

I’ve just been through this pain too!

I believe standard fan switch on is 106DegC (for an NA car, you don’t say if turbo or NA). If you’re using OBDTuner software this is variable so it may be worth checking that setting too.

I’d swap the relay to the horn position and test that.

Then run the car up to fan temp and look for a signal and look for the ecu signal at the relay base.

If you still have no luck it gets a bit more complicated!

[stevieturbo]

First you need to be sure the ecu is actually commanding the fan to be on.

 

Then check for the ecu ground trigger at the relay base. You could manually short this to ground for a test which should energise the relay and bring fan on, if the power wiring/fuse is also good.

 

 

 

 

 vx220 front relays2.jpg   167.12KB   1 downloads

 

 

[VincentL]

Swapped the relays and ran up to 101C after that i went and cruised to bring the temps down as the fans did not come on (This is a tubby). @stevieturbo, since i'm a complete pleb can you explain a bit more? Instead of shorting the pins under the relay I should be shorting F12?

 

I'm more used to computer programming/hacking than electronics 

Edited by VincentL, 19 May 2024 - 08:24 AM.

[stevieturbo]

Then talk to the ecu and trigger the fan circuit that will test things. Really, first and foremost you need to know if the fan is even expected to be on.

 

As indicated on the drawing, you will have a 12v feed at pin 30 ( can't remember if this is also with ignition off, but I think it is permanent )

 

30 will be fed from the fuse box as also indicated.

 

So first test that you have 12v at terminal 30, tested referenced to battery ground with a  suitable meter or lamp.

 

If so, and you were to remove the relay and bridge terminals 30 and 87 with a piece of wire and two standard spade terminals ( or just shove wire in carefully ), the fan should operate.

 

If no 12v, then you likely need the ignition turned on, or a fuse has blown etc but I'm almost sure it's a permanent 12v there via the fuse.

 

So in brief, with ign on, you should see 12v at pin 86 and 30 when tested against battery ground.

 

Pin 85 will only only ground when the ecu asks for the fan. Test this with your meter red wire attached to battery 12v, and the black wire to pin 85. You should see 12v when fan is ON.

 

Or if you unbolt the relay holder, flip it upside down to access the terminals from the underside and manually apply a ground to pin 85 with relay plugged in, this should trigger the relay and activate the fan, basically you simulating the ecu triggering the relay. The yellow relay base also has pin numbers marked.

This is a small Blue/Grey wire, 85.

Pins 86/30 are Black/Brown perm 12v.

Output to the fan is Black/Green

 

 

Various videos on testing relays etc

 

 

 

 

[Ivor]

Swapped the relays and ran up to 101C after that i went and cruised to bring the temps down as the fans did not come on (This is a tubby). @stevieturbo, since i'm a complete pleb can you explain a bit more? Instead of shorting the pins under the relay I should be shorting F12?

I'm more used to computer programming/hacking than electronics

Think fan is set at 104?

[Ivor]

97 for a turbo, 106 for an NA:
http://www.vx220.org...ld-fan-come-on/

[Ivor]

Worth checking that the fan on temp has not been changed in the ECU?