Fan Cuts In Very Late On 1.9 Gti

[Weser 30]

Once again I have got to turn to the people on here for a bit of help.

 

basicly on my 1.9gti the fan/fans on the rad cut in only when the temperature is very hot. Im sure they used to cut in earlier but I haven't driven it fo a while.

Now on my 1.6 cti the fan cuts in at about half way up the temperature gauge. But like I said on the 1.9 it doesnt cut in till at least 3/4s of the way up!

 

I haven't started stripping anything down yet so have a few questions.

- How many fans does the 1.9gti have?

- On the temperature sensor in the rad it has 3 wires. One is permantly live and if I bridge this with the middle one the fan/fans come on. If I bridge the permant live with the other wire I get nothing.

- Now im sure the fan/fans have 2 speeds. Is it possible mine is just running on the high speed?

 

Anyone that knows anything on this I would be greatful for info as I dont want to overheat!

 

Cheers

[Anthony 1,003]

Sounds like the slow-speed setting of the fan isn't working, so the fan isn't coming on until it gets very hot and goes to full-speed.

 

The slow-speed fan is driven through the resistor that is clipped (or was once clipped) to the top of the radiator.

[Weser 30]

So am I right in thinking there is two fans. One that runs flat out at the high temp and one that runs slow through the resistor?

 

Have you got any photos of where the resistor is? Because I take mine will be loose wires now.

 

It all makes sense now as I looked at the wiring digram in the haynes manual last night. But I thought that said one fan. So the slow speed runs and then when the temp gets higher it has more voltage making it run faster? Is that correct?

 

Would the problem be down to my temperature sensor on the low speed? I take it no if the fan didnt come on when I bridged the wires.

 

Sorry so many questions

[Anthony 1,003]

Just a single fan - the fan thermoswitch sends the current for the fan through the resistor on slow-speed upto a given temperature, and direct to the fan on high-speed if the temperature gets hot enough. Given that shorting 12v with one of the pins made the fan run, and with the other pin didn't, I'd guess the problem lies with the resistor.

 

I don't have a picture, but it's a 3" long metal cylinder that is normally clipped to the top of the radiator, but on many/most cars it is usually somewhere behind the passenger headlight - follow the various wires from the fan loom and you'll find it. Don't confuse it with the similar looking dim-dip resistor that's bolted on the headlight panel below the passenger headlight

 

If the resistor is faulty, you could just join the two wires leading to it together - that will make the fan come on at full-speed instead of slow-speed (as the current no longer runs through the resistor)

[Weser 30]

Just a single fan - the fan thermoswitch sends the current for the fan through the resistor on slow-speed upto a given temperature, and direct to the fan on high-speed if the temperature gets hot enough. Given that shorting 12v with one of the pins made the fan run, and with the other pin didn't, I'd guess the problem lies with the resistor.

 

I don't have a picture, but it's a 3" long metal cylinder that is normally clipped to the top of the radiator, but on many/most cars it is usually somewhere behind the passenger headlight - follow the various wires from the fan loom and you'll find it. Don't confuse it with the similar looking dim-dip resistor that's bolted on the headlight panel below the passenger headlight

 

If the resistor is faulty, you could just join the two wires leading to it together - that will make the fan come on at full-speed instead of slow-speed (as the current no longer runs through the resistor)

 

 

Cheers Anthony. I understand it has all "clicked" now.

 

I will have a look tonight!

[smithy 1]

Cheers Anthony. I understand it has all "clicked" now.

 

I will have a look tonight!

 

 

do what i have done replace the temp switch with a 2 pin type and do away with the resistor completely also wired it to switch earth now to energise a relay that controls the earth to fan motor.

the coil pos on relay and fan pos are permanent lives from small shunt box so are fused aswell.

 

the rad fan temp switch contacts burn out due to switching a live.