Two Speed Fan Inoperative
 

I know that this question has been asked many times and in many different ways but there would appear to be many answers!

This is the situation on a 2004 CDTi with 101195.on the clock.

I have no fan operation at all and looking through the front I have a gold resistor at approx. two o’clock so we are looking at a two speed fan that has had the resistor upgrade.

With AC off all is well but eventually we do get the temperature gauge to nine o’clock if waiting for car parks or the usual slow city driving but as yet it has not risen beyond this and county driving is no problem but the fan is still not working.

With AC turned on the engine temperature rises quicker and I get erratic running (as someone else said it’s almost like someone is tapping the accelerator pedal) at low revs and even up to 15000 that becomes more pronounced as the temperature rises but again we do not seem to be exceeding the nine o’clock threshold as fare as engine temperature is concerned but engine fan is still not running.

As the fan /temperature control is so linked in with other parameters within the engine could it be that one of these is not releasing the fan command for some reason or another.

What I don’t want to do is get my garage to take the front off the car (probably £200) only to find that the AC needs regassing and that’s it.

Has anyone had these symptoms exactly or is it just so vague regarding the fan etc. that it could be anything?

Peter

Hi pcully,
as you have a diesel the first thing to do is to switch on the ignition and press the windscreen demist button on the climate control panel. Then go to the front of the car and look through the grill and see if the fan is turning.

If the fan does not turn suspect an open circuit resistor. If the fan turns, all is well.

The erratic running of the engine may be some other problem such as EGR not closing correctly

Pete.

OK I have checked the front end and so fare we have no rotation of the engine fan

You have a faulty cooling fan assembly.
The first suspect to try is the gold resistor. If you can place a wire link across resistor and then try the test again, this will tell you if the resistor is open circuit or not. If the fan turns fast the resistor is faulty, if the fan does not turn the you have a faulty motor, a faulty control box (mounted on the rear of the fan assembly) or a missing supply voltage.

don't be misled by the temp gauge, it stays at 9 o'clock from 75/110C and if and when it does move above that it'll be so quick risk of damage is already high, often and regularly referred to as made of chocolate

OK so first job check the fuses ASAP

No Peter; I'm afraid that the first job is to follow Union Wheels' advice in post number 4. Your gold resistor is the prime suspect at the moment.

Simon

Very common scenario these days for 2 speed fans !!

The resistor may be u/s.
If it's been u/s for a few months and the AC has been used,
The fan will have only been operating on HIGH speed cycling on and off every few seconds. (this puts excessive current through the high speed relay. They are rated at 40 amps and the 65 amp surge with sudden high speed demand welds the contacts together eventually)

AC should not be used if SLOW speed isn't working as the resistor acts as a "soft start" circuit for the HIGH speed.

If the resistor is OK and high speed relay in the control box is OK you are looking at a duff motor or corrosion in the factory wire joints between the fan plugs/ control box and motor itself or the 80amp fuse.
The fuse very rarely fails but when it does it will be for a reason.

Happy fault finding and if you need a new motor kit look no further :smilie_re:


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Peter I forgot to mention the engine hunting is caused by the fact you have no cooling for the engine or AC compressor.

The HP pipe and compressor will be screaming hot without the fan operation and the HP pressure (if connected to R134 gauges will probably be reading 25-30 BAR pressure!!!)


Normal pressure is 6 - 8 BAR so the bottom line is don't use the AC until the fan has been replaced or fixed. You can use the AC above 30 MPH if you really must but are you going to remember to switch it to ECON (economy AC off ) every time speed drops below 30. :shrug:

Same here
 

I have the same problem with my diesel .

I put in a new two sped fan with resistor last year . All was well .

Checked the fan the other day and noted the fan did not come on with demist. Changed the silver resistor to gold and this made no difference.

Put paper clip across the triany and still no life.

How can i test the fan motor or relay pls.

Many thanks