'97, 2.5 DSE P38 heater fan fault

So, my fan works..... sometimes, no rhyme or reason to it, one day I can jump in and everything works, fan goes like the clappers when you turn it up... other times it doesn't work at all. Odd thing is, sometimes I can shut the engine down, take the key out, then put the key back in and start it up and the fan works again, but sometimes it doesn't. I'm guessing there's a dodgy connection somewhere, but where do I start looking?

The viscous fan, you mean?

Grrr read the bloody title!

Sorry Grrrrrr!

Dirty hevac panel! Sometimes I put mine to auto and get different levels of fan speed and then it goes into auto climat control and some days it behaves.

I just leave it on auto!

Same here! Well most of time unless it changes it bloody mind :-(

Grrrrrr said:

I just leave it on auto!

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Doesnt even work on Auto

Try some contact cleaner on it, you may be lucky. That or its a refurb job...

There are controller transistors on each fan, that turn them up and down as required. A repair kit is available to replace them. Look at this and note the two large transistors on the fan speed control unit.

wammers said:

There are controller transistors on each fan, that turn them up and down as required. A repair kit is available to replace them. Look at this and note the two large transistors on the fan speed control unit.

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Ooooo... playtime on the weekend, relays to disassemble first, then if no joy, blower motors, Christ, they wern't kidding when they said you better be prepared to get the spanners out if you own a P38 lol!

Boom, there he is! Well done wammers to the rescue. Every weekend is range rover weekend!

Transistors are FW26025A or better is MJ11015G. http://www.ebay.co.uk/itm/2-x-ON-Se...636591?hash=item4af37d04af:g:FXQAAOSwwbdWO5wU

wammers said:

Transistors are FW26025A or better is MJ11015G. http://www.ebay.co.uk/itm/2-x-ON-Se...636591?hash=item4af37d04af:g:FXQAAOSwwbdWO5wU

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Well, its not the relays, found an Ohms meter and taught myself how to use it (good old you tube lol), took the relays apart, cleaned them, and then checked them on the meter, working fine, guess its time to take the blower motors out.... Saturday better be dry!

wammers said:

Transistors are FW26025A or better is MJ11015G. http://www.ebay.co.uk/itm/2-x-ON-Se...636591?hash=item4af37d04af:g:FXQAAOSwwbdWO5wU

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Just looked at pics of the transistors and they seem to be two pin, although they are listed as being PNP's (three pin?), how do I test them, is the metal case the third pin?

WayneRR4x4 said:

Just looked at pics of the transistors and they seem to be two pin, although they are listed as being PNP's (three pin?), how do I test them, is the metal case the third pin?

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You don't you just change them but i suppose you would be looking for an open circuit.. Have never done it but it is a well know fault. There used to be repair kits on Ebay to do this. As far as i know the first number listed is the original and the second number an uprated alternative.

wammers said:

You don't you just change them but i suppose you would be looking for an open circuit.. Have never done it but it is a well know fault. There used to be repair kits on Ebay to do this. As far as i know the first number listed is the original and the second number an uprated alternative.

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So, do you buy the parts first, and then hold them or re-sell them if it turns out to be something else, or take the blower fans out first, clean the relay and see if that works before buying the transistors? I was just asking about testing as I can see all 4 (2 on each blower fan) being duff at the same time, so I would test to see which ones (if any) are the faulty ones.

WayneRR4x4 said:

So, do you buy the parts first, and then hold them or re-sell them if it turns out to be something else, or take the blower fans out first, clean the relay and see if that works before buying the transistors? I was just asking about testing as I can see all 4 (2 on each blower fan) being duff at the same time, so I would test to see which ones (if any) are the faulty ones.

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EDIT - can't see, not can

WayneRR4x4 said:

EDIT - can't see, not can

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Only one each side needs to be duff but you would not just change the duff one would you. Up to you, i can only say what it maybe. The relay is for high speed only, transitional speeds are controlled by the speed controller. So if the fans only work at high speed the relay will be fine, if they do not work properly on intermediate speeds the transistors will need looking at.

wammers said:

Only one each side needs to be duff but you would not just change the duff one would you. Up to you, i can only say what it maybe. The relay is for high speed only, transitional speeds are controlled by the speed controller. So if the fans only work at high speed the relay will be fine, if they do not work properly on intermediate speeds the transistors will need looking at.

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Ok, I may have solved the problem more simply, just found blowers for £15 each inc P&P, told them to send me two, I'll swap them, and then set about testing the crap out of the old ones in the comfort of my kitchen when I have time, if I find faults with transistors etc I'll buy new, refurb the units and sell them, even if I only break even it will be a win for me. Thanks for your help, I hope my continual posting about various things isn't too annoying, I'm just keen to do as much as possible myself, but got very limited knowledge.