Cooling fan not coming on?

Temp gauge reads ok when hot. Tried changing fuses on top of bat but nothing.

Any ideas?

Cheers.

Pull the connector off the temp switch on the radiator then short pin 2 to pin 1 and the fan should run @ low speed and if you short pin 2 to pin 3 it should run @ high speed, if this works your temp switch is duff, it does'nt work you have a problem from the fuse to the temp switch plug, if it works on low speed but not high speed the fan control unit (under the battery tray area) is @ fault or the metal fusable links on top of the battery, they often look OK but you need to remove them and check they have'nt fractured

Pull the connector off the temp switch on the radiator then short pin 2 to pin 1 and the fan should run @ low speed and if you short pin 2 to pin 3 it should run @ high speed, if this works your temp switch is duff, it does'nt work you have a problem from the fuse to the temp switch plug, if it works on low speed but not high speed the fan control unit (under the battery tray area) is @ fault or the metal fusable links on top of the battery, they often look OK but you need to remove them and check they have'nt fractured

nice one, will give that a bash.

Pull the connector off the temp switch on the radiator then short pin 2 to pin 1 and the fan should run @ low speed and if you short pin 2 to pin 3 it should run @ high speed, if this works your temp switch is duff, it does'nt work you have a problem from the fuse to the temp switch plug, if it works on low speed but not high speed the fan control unit (under the battery tray area) is @ fault or the metal fusable links on top of the battery, they often look OK but you need to remove them and check they have'nt fractured

nice one, will give that a bash.

sorry for the late post, eventually got time to try and sort this. Right I short pinned it every way possible and can only get the hi speed fan working. So changed temp switch in rad, filled it back up with coolant and took for a drive. No fans are coming on.

On inspection the bottom hose for the rad is cold but before i changed the temp switch it was hot?????

Temp still sits at just above 90 when hot.

Any ideas?

Have you checked the fan connector? I have seen the pin come loose and go out the back of the plug when pushed inn look into the connectors, there could be a coroded connector or maybe a pin is bent etc. Not100% but is the gti fan connector on thefan body, or ons section of wire? Ifitso the wore then it could well be the wire connections that are at fault. Have you tried putting power straight to the fan?

Have you checked the fan connector? I have seen the pin come loose and go out the back of the plug when pushed inn look into the connectors, there could be a coroded connector or maybe a pin is bent etc. Not100% but is the gti fan connector on thefan body, or ons section of wire? Ifitso the wore then it could well be the wire connections that are at fault. Have you tried putting power straight to the fan?

the electrical plug seems fine on the inside and when i put a paper clip between the live and the fast fan speed it works fine,

Just not on the low speed. And when i connect up the plug to the senor i get nothing when it hits 90.

there was loads of green stuff round the old sensor which shows signs of corrosion so it could be that some coolant has got into

one of the pins in the plug, but that still wouldn't explain why it would not come on at 90.

Will have to check all the wiring and fuses again.

Am I correct in saying that if it was the water pump or thermostat that was fecked then the car would be over heating?

If the pump was gone then the heater in the car would be cold usually. The thermostat if stuck would either make it over heat or under heat where by the temp would drop when moving.

Which sensor did you change? The one in the stat housing? As there is also one in the radiator I think, but I'm not sure if that's for the fan?

Also, as this is an air con model it has a fan controller (black box) somewhere near the battery. This I believe is what controls the low speed setting, as it will use that when the ac is on.

Also, does it have two sensors near the thermostat? As again, ac cars should have an extra for the ac system and I think if that fails then it doesn't tell the controler, maybe? But I could be totally wrong and I'm sure someone will be along to correct me if so.

If the pump was gone then the heater in the car would be cold usually. The thermostat if stuck would either make it over heat or under heat where by the temp would drop when moving.

Which sensor did you change? The one in the stat housing? As there is also one in the radiator I think, but I'm not sure if that's for the fan?

Also, as this is an air con model it has a fan controller (black box) somewhere near the battery. This I believe is what controls the low speed setting, as it will use that when the ac is on.

Also, does it have two sensors near the thermostat? As again, ac cars should have an extra for the ac system and I think if that fails then it doesn't tell the controler, maybe? But I could be totally wrong and I'm sure someone will be along to correct me if so.

AC working fine mate, Its the fan swich in the rad that i changed and yes it does have a control unit under battery. Glad to hear its nothing major then.

I think it could be the control unit or a broken wire or fuse.

I will get to the bottom of this yet.

Edited 12 August, 201312 yr by watson

Hello I have the same trouble I can't get the fan to come on at all. Have crossed the pins ,will try the other tests on here been looking for some advice and now found some..Great.

Hi everyone and thanks for this thread. I am having a similar problem with my '99 6N Polo which does have a/c. There is no power in the red wire of the radiator thermo switch, I have checked the fuses on top of battery and inside the fuse compartment and they all fine. Can somebody advise as to what would be the problem in this matter. I haven't checked the cooling fan module relay yet, if I do what would be the telltale sign for failure to look for.

Thanks

Hi everyone and thanks for this thread. I am having a similar problem with my '99 6N Polo which does have a/c. There is no power in the red wire of the radiator thermo switch, I have checked the fuses on top of battery and inside the fuse compartment and they all fine. Can somebody advise as to what would be the problem in this matter. I haven't checked the cooling fan module relay yet, if I do what would be the telltale sign for failure to look for.

Thanks

Sorry forgot to mention that when I connect fan straight to battery I do get both speeds on fan, but when I bridge the terminals nothing happens.

Thanks

The supply for the switch ( red/yellow wire pin 2) comes direct from the fuse on top of the battery ( 20 amp ) the low speed should run if pins 1 & 2 are shorted together regardless of the fan control unit, but if you don't have a supply on pin 2 nothing will work !

Thanks for the response Nige8021, nothing happens when I short 2 &1 and neither happens with 2 & 3 short whereas the fuse is okay. But when I. Connect wire straight from battery positive to 2 I do get the low speed and the high on 3. Where else could be the problem if fuses are okay...the fan doesn't even start when I switch on the a/c.

Thanks

Edited 2 August, 201411 yr by Thasbo

Without the supply on pin 2 neither the low or high speed will work with AC on or off, so I would re inspect the fusebox on the battery and check for any corrosion on the contacts

_{Thanks a million Nige8021 for the advise, pulled out the fuse and found greenish build up and I sprayed a bit of electric cleaner and replaced with new fuse and now my is working okay even via the thermo switch from the radiator. Thank you so much, now my only worry is when I switch on my a/c it does not kick in, for now it's only working on the coolant temp.}

Thanks once again...

If its not kicking into high speed, with the AC on it'll be the fan control unit, mounted under the battery tray area on the chassis leg, they also suffer from internal corrosion

If its not kicking into high speed, with the AC on it'll be the fan control unit, mounted under the battery tray area on the chassis leg, they also suffer from internal corrosion

Hi Nige8021

its not kicking at all when you press the aircon button...could it be anything on the aircon side say like Gas, compressor, pressure as I have not used the aircon for about 2 years.

Thanks

OK with that info, I'd start with getting the pressures and oil levels checked, there is also a recent posting about problems with the compressor clutch

Thanks Niga8021 I have checked the the posting and its quite helpful for my situation....

Thanks

Hi Nige821,

thanks for your advise, finally gased up the aircon and its working like a dream. You wrre spot on with the pressures and the oils, seemingly what was preventing the compressor from engaging was due to the low pressure or rather no gas at all. It is a safe sort of prevention tfrom running the compressor when there is no lubrication from the gas.

Thanks

Yes if the gas pressure is too low the controller will prevent the AC system from engaging too stop damage to the compressor