Fans not kicking in/over temping

[drka-drka]

Help!!!!

Recently topped up my air con for this lovely weather we have been having worked fine for a couple days then when I was stuck in traffic the other day I noticed my engine temp bouncing off the 120 degree stop on the gauge and the beep going off.

Upon further investigation iv found my fans aren't kicking in at all with aircon on or not. I'm in a couple of minds what it is.

I had a read of the guide in the F&Q section about fitting your own resistors in but I'm not 100% if its the low speed fan side of it as they aren't coming on at all.

Could it be the fans themselves or the control for the fans? Just before I go down the wrong route wondered if anyone had also had this problem?

It's bloody hot at the moment so this would be handy of my engine could be kept cool and air con worked

 

[brad_barker12]

if your fans aearnt kicking in at all then its possible the fuse has blown. under the bonnet lift the battery cover and check they all look ok.

its common for these to blow if the low speed fan resistor has packed in and the high speed is used all the time to cool the engine. eventually the fuse blows due to the amount of power the high speed uses.

 

[drka-drka]

Fuses are all fine 1st thing I checked. Should have said oops

 

[brad_barker12]

mmm thats strange. my LCR has the low speed fan resistor fault. but my high speed still works although occasionally the temp creeps a little over half way on the temp gauge before the fans kick in. im looking into either replacing the fans or doing the resistor mod.

when i switch my A/C on the fans kick in around 10 seconds later. so something is definately not right.

 

[aymen_a22]

There is a triangular connector that plugs into the thermostatic switch on the right side of the radiator in next to the battery. If you unplug that and bridge two pins at a time you can manually activate the low and high speeds.

I would try that first to check that your fans are not broken, if they do not turn on then it would point straight to the resistors.

There is a guide on YouTube somewhere, try searching Vw radiator fan resistor or something similar.

 

[aymen_a22]

YouTube search Vw fan test and it is the first one.

 

[Seal_LCR]

Let me or Tim know if your struggling as we have a spare set that work

 

[james.l]

You can make your own resistors and wire them in like I have done. Other option is a nime fan controller if your not up to cutting your wiring to put your DIY resistors in. I'll see if I can dig the DIY resistor mod out for you...

EDIT: Here's the link

http://www.billswebspace.com/VWMKIVClimatronicFanRepair.htm

 

[brad_barker12]

I bought the resistors and everything I needed to complete the resistor mod to the radiator fans as per the how to thread on here. Fans work perfectly now. Very happy with it. Looks OEM aswell

 

[6th.replicant]

FWIW, a few summers back, my LCR's temp would creep up to 95ish in traffic and the fans were slow to kick-in. Turned out that the fuse pack that lives on top of the battery was 'fried'.

Replacement only available as one unit. Bought mine from SERE. No probs since

 

[benturner]

My fans will not activate. I have read many threads but not found the answer yet.

I tested the radiator thermoswitch by shorting the pins. Both high and low speed settings work fine when shorted when the engine is running. Only the low speed works when ignition is off.

Until recently I was using my AC as a cooling backup as it was running the fans on a low speed to cool it's compressor, this was also offering cooling for my rad. AC recently packed up so now I have no fans running at all. I think that may be a case of low gas shutting the compressor down as described in other threads. I shorted the thermoswitch again to check the resistors hadn't gone and both speeds work fine when shorted.

I replaced the thermoswitch but it made no difference. I tested the old one in a frying pan on the hob. Both the LOW and HIGH temp switching seems fine.

Possible problems:
1. Is the new thermoswitch dead? Seems unlikely but it was an online purchase?! Also doesn't explain why the old switch didn't work when actually it seems fine when testing it in the frying pan today?!

2. Is there a dodgey connection to the 3-pin thermoswitch? Seems unlikely as the plug looks to be in good shape and the switch is new.

3. Is the water in the radiator not getting hot enough to activate the thermoswitch (I think this is unlikely due to having a recent thermostat change and the water pump was changed 9 months ago). Don't know if they put in a plastic or metal pump but I notice good cooling when the car is moving which implies water is passing through the rads.

4. Is the green temp sensor giving excessively high temperature readings to both the ECU and instrument panel? Seems unlikely as it's new and from a decent German dealer online. Plus the OBD reading seems to match the dashboard reading quite well.

5. Is the fan control unit faulty? Seems unlikely after both speeds worked fine when shorting the thermoswitch terminals.

I NEED EXPERT HELP Any bright ideas out there?

 

[dreago 1]

FWIW, a few summers back, my LCR's temp would creep up to 95ish in traffic and the fans were slow to kick-in. Turned out that the fuse pack that lives on top of the battery was 'fried'.

Replacement only available as one unit. Bought mine from SERE. No probs since

Hi was there any visual evidence as this sounds familiar. I was parked with the engine on this morning after driving to work. The temp crept up to 95-100 and sat their for 5 mins then the fans would kick in and it eventually went down. It would then go back up to 95-100 again. Sound similar?

G

 

[benturner]

They DO work!

Rather than kicking in at the expected temperatures they come on at around 110–115degC. Im pretty sure despite this high temp it is the low speed that comes on first. I'm thinking that the perceived temp of the green temperature sensor is actually much higher than the actual temp of the radiator fan thermoswitch. The reason my AC no longer works is due to a leak that is being sorted today. The fans it seems are in full working order.

Thanks for your comment anyway!

Kind regards,
Ben

 

[tombo]

My fans will not activate. I have read many threads but not found the answer yet.

I tested the radiator thermoswitch by shorting the pins. Both high and low speed settings work fine when shorted when the engine is running. Only the low speed works when ignition is off.

Until recently I was using my AC as a cooling backup as it was running the fans on a low speed to cool it's compressor, this was also offering cooling for my rad.

Ben, I have this problem. I'll be changing the switch tomorrow and hope it works. Surely if yours is not coming on till that high temp there is something wrong? Is the switch not calibrated to come on at about 87 for low speed fans?
I have only ever seen my fans on with air con, they wont cut in otherwise but the temp readings don't go above 90.

 

[benturner]

I think the high temp is not really that high. I think the modified green temp sensor I put in has a higher reading for better engine performance. Just a thought, I've not tested it at all. That would explain the temp appearing to be much higher in ECU and dash. The original thermoswitch on rads must be working as designed. I'm no expert! The garage tested the fans simply by leaving the engine to overheat. Only when it crept up to 115 degrees did the fans kick in. In reality this 115 reading on dash and ECU is probably actually nearer the proper thermoswitch threshold temps

 

[tombo]

Thanks Ben, I'll have a go and let you know. I've also changed to green temp sensor due to fluctuating temp gauge on dash.
Tom