Coolant Fan Stays Running Until Battery Dies? Help

[Ibiza08L]

Hello, this is my first post on this site, nice to be here

I have a Seat Ibiza 6L (08 plate), 1.4 petrol (BBZ engine).
Pretty much, when the cooling fan kicks in (when the car gets up to temp or AS SOON AS I turn the AC on), it will not turn off on its own ie when the car is switched off. It will stay running until it has drained the battery flat. I used to disconnect the battery to stop it but have now found that, if I pull the fan control relay fuse on top of the battery, the fan will turn off! However, the issue doesn't seem to be down to the control module itself.

I have replaced the fan control module and also changed the coolant temp sensor as per previous advice, but the problem still persists. Again, the fan will turn off when I pull the control module fuse, will this help narrow down the problem? I know there have been similar threads but I haven't seen a solution for my specific issue. Thanks in advance for any help!

 

[RUM4MO]

Have you considered that the fan control relay that you are unplugging, might be holding "on" after its coil supply has been removed, and only you pulling it out and it cooling off and/or the additional physical shock of it getting pulled out is releasing the maybe arcing and temp holding contacts?

 

[Ibiza08L]

Have you considered that the fan control relay that you are unplugging, might be holding "on" after its coil supply has been removed, and only you pulling it out and it cooling off and/or the additional physical shock of it getting pulled out is releasing the maybe arcing and temp holding contacts?

I haven’t no. If this was the case what would a potential solution be?

 

[BigJase88]

I haven’t no. If this was the case what would a potential solution be?

New relay

could be sticking contacts as mentioned above.

the relay is a relatively inexpensive item

 

[Ibiza08L]

New relay

could be sticking contacts as mentioned above.

the relay is a relatively inexpensive item

The radiator fan relay? I’ve changed this before and didn’t fix the problem

 

[Ibiza08L]

I was thinking maybe a temp/radiator switch? Not sure if this the next step and also the location of said switch

 

[RUM4MO]

So, you have replaced the first, under bonnet cooling fan relay for a genuine new one, the fan control thermal switch for a genuine new one and the fan control module block that is fixed low down for a genuine new one - and you still have this issue that only starts to happen after the coolant has reached the normal "fan switching on" temperature?

Have you tried switching the cooling fan on at low speed and high speed by applying a shorting link across the correct pins with the thermal switch unplugged? If so how does it behave, ie do both the low speed and high speeds run and stop when you remove the link?

If so it sounds a bit like you have a wiring issue somewhere.

 

[Ibiza08L]

a was

So, you have replaced the first, under bonnet cooling fan relay for a genuine new one, the fan control thermal switch for a genuine new one and the fan control module block that is fixed low down for a genuine new one - and you still have this issue that only starts to happen after the coolant has reached the normal "fan switching on" temperature?

Have you tried switching the cooling fan on at low speed and high speed by applying a shorting link across the correct pins with the thermal switch unplugged? If so how does it behave, ie do both the low speed and high speeds run and stop when you remove the link?

If so it sounds a bit like you have a wiring issue somewhere.

Ah, I think I am miscommunicating. My technical language is not the best sorry. I have changed the control module low down, and i have changed the coolant temperature sensor. Aside from this, I haven’t changed anything else. Where is the relay under the bonnet located? Also where is the fan control thermal switch located? Thanks

 

[RUM4MO]

It is not the coolant temperature sensor, that you should have replaced, it is the coolant thermal switch which is fitted into the radiator and has a big connector on it. The coolant temperature sensor is fitted to the engine and only provides coolant temperature to the engine ECU and in other marques like VW the temperature gauge.
You said that you unplugged a fan control relay, so without checking, I believed you and considered that there was yet another master control relay, but I'd doubt if there is any need for one.

So if that is correct, the cooling fans control module switch the fans on directly and are supplied by a power source and fed with control lines from the coolant thermal switch and the AC system.

Edit:- further facts, the part that I suggested you replace - or first check, is a plastic bodied thing that is screwed into the top engine facing part of the radiator, the coolant temperature sensor is held into its position on the engine by a black C clip.
To check if the thermal switch is what is keeping the fans running, remove its plug while the fans are running on - when they should not.

 

[Ibiza08L]

It is not the coolant temperature sensor, that you should have replaced, it is the coolant thermal switch which is fitted into the radiator and has a big connector on it. The coolant temperature sensor is fitted to the engine and only provides coolant temperature to the engine ECU and in other marques like VW the temperature gauge.
You said that you unplugged a fan control relay, so without checking, I believed you and considered that there was yet another master control relay, but I'd doubt if there is any need for one.

So if that is correct, the cooling fans control module switch the fans on directly and are supplied by a power source and fed with control lines from the coolant thermal switch and the AC system.

Edit:- further facts, the part that I suggested you replace - or first check, is a plastic bodied thing that is screwed into the top engine facing part of the radiator, the coolant temperature sensor is held into its position on the engine by a black C clip.
To check if the thermal switch is what is keeping the fans running, remove its plug while the fans are running on - when they should not.

I removed the thermal switch plug whilst the fans were running today. They continued to run. Is it worth changing the switch out anyway?

 

[Ibiza08L]

So, you have replaced the first, under bonnet cooling fan relay for a genuine new one, the fan control thermal switch for a genuine new one and the fan control module block that is fixed low down for a genuine new one - and you still have this issue that only starts to happen after the coolant has reached the normal "fan switching on" temperature?

Have you tried switching the cooling fan on at low speed and high speed by applying a shorting link across the correct pins with the thermal switch unplugged? If so how does it behave, ie do both the low speed and high speeds run and stop when you remove the link?

If so it sounds a bit like you have a wiring issue somewhere.

I will try the shorting link step tomorrow

 

[RUM4MO]

I removed the thermal switch plug whilst the fans were running today. They continued to run. Is it worth changing the switch out anyway?

No, that thermal switch is currently not the root cause of your problem.

When you replaced the fan controller assembly, did you fit a new one, or a used one? If you fitted a used one, then maybe it also has the same usual failure as your original one had.

 

[RUM4MO]

I will try the shorting link step tomorrow

It might be useful to try that while the engine is cold and the fans are not running, if only to see if that second fan controller is working at all.

 

[Ibiza08L]

No, that thermal switch is currently not the root cause of your problem.

When you replaced the fan controller assembly, did you fit a new one, or a used one? If you fitted a used one, then maybe it also has the same usual failure as your original one had.

I fitted two second hand ones, but they may have both been faulty. I will try and replace the module with a new version and see if that solves anything, as well as testing out my thermal switch. Anything else you suggest I can do whilst I’m going under the car?

 

[RUM4MO]

I fitted two second hand ones, but they may have both been faulty. I will try and replace the module with a new version and see if that solves anything, as well as testing out my thermal switch. Anything else you suggest I can do whilst I’m going under the car?

Just check that the cabling associated with the fan control assemble looks undamaged along its length - ie as far as you can see/feel.

When applying jumpers to the unplugged thermal switch connector(the cableform side), make sure that you don't short anything or that will blow some fuse(s).

 

[Ibiza08L]

Just check that the cabling associated with the fan control assemble looks undamaged along its length - ie as far as you can see/feel.

When applying jumpers to the unplugged thermal switch connector(the cableform side), make sure that you don't short anything or that will blow some fuse(s).

So I tested the connector today. Both low and high speeds kick in. High speed turns on and off fine, no sticking. But low speed sticks as soon as it turns on. Does this bring me any closer to a solution? Control module again perhaps?

 

[RUM4MO]

I'd think so, it does sound like the slow speed relay is sticking on for some reason, pity that you have not yet left it running like that then taped or hit the relays on the controller while the fan is still running but that connector still unplugged at the radiator and the jumper links removed - really to make sure that it is a sticking relay and not a low or weak feed to that relay from another source - though I don't think that there is another switching demand source for the slow speed, I think that the AC running only switches the fan high speed windings.

 

[Ibiza08L]

I'd think so, it does sound like the slow speed relay is sticking on for some reason, pity that you have not yet left it running like that then taped or hit the relays on the controller while the fan is still running but that connector still unplugged at the radiator and the jumper links removed - really to make sure that it is a sticking relay and not a low or weak feed to that relay from another source - though I don't think that there is another switching demand source for the slow speed, I think that the AC running only switches the fan high speed windings.

I could give this a try now? What if when I hit the relays a bit and the fans still don’t stop?

I think it’s probably wise to order in another control module anyway. Where would you suggest getting a new, genuine part?

 

[RUM4MO]

If your car is cold and you fit the slow speed jumper and the fan(s) run at the slow speed and stay running when you the jumper, and you can't stop the fan(s) running by hitting or taping the relay on the board, then it could be a wiring fault - though I'd still think that it is that fan controller.

If you buy a used one from ebay, I'd hope that that seller would have tested it before putting it up for sale, so if it fails contact them for another one to get sent out.

I'm guessing that you still have the original one and know its part number so that you are buying the exact correct part, though I'd guess that newer versions should also be compatible.

 

[Ibiza08L]

If your car is cold and you fit the slow speed jumper and the fan(s) run at the slow speed and stay running when you the jumper, and you can't stop the fan(s) running by hitting or taping the relay on the board, then it could be a wiring fault - though I'd still think that it is that fan controller.

If you buy a used one from ebay, I'd hope that that seller would have tested it before putting it up for sale, so if it fails contact them for another one to get sent out.

I'm guessing that you still have the original one and know its part number so that you are buying the exact correct part, though I'd guess that newer versions should also be compatible.

When I’m tapping nothing is happening although I don’t think I’m doing it properly/ hitting in the right places. When I unplug the connector from the fan module the low speed turns off. Going to order another module and see how that goes