fan dead - final stage resistor

Nov 04, 2005 11 Replies

Hi all, I have a 97 BMW 528 and the interior fan has died.



A little browsing on the newsgroups suggests a popular cause is the final stage resistor, and I have found some pics of where it is located in the car.



How much is a final stage resistor in UK?



Can these resistors be tested with a meter in the usual fashion to prove it is faulty before I buy a new one?



If so, what are they rated at?



Are there any other common causes - a fuse possibly and if so, where is it found?


TIA


Ho ho ho! I don't believe it ...

It just died on our 525 TDS (1998) last week. Perhaps these things have an in-built timer?

The dealer we took it to said that the "diagnostics" had found that the resistor is faulty. They replaced the resistor ... twice ... but it didn't work. Now they need to try a new motor. That will involve taking the dashboard out to get at it. I dread to think what the bill will be.

Good luck - I hope it really is the resistor with yours.

Jo

Roughly 60 quid.

I've got no information on that.

Forget trying to replace it with something else - or repairing it. Unfortunately.

Mine cost £57.50 inc VAT in July.

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Hmmm, the diagnostics aren't up to much then. Was it a BMW main dealer? Thanks for the reply and good luck.

Thanks, that's useful. Don't suppose you tested the old & new resistors with a meter? I don't wanna buy one only to find it's not the cause.

I was thinking that if I knew what it measured I'd take my suspect one out and check it before I bought a new one. Might try a local BMW indy shop to see if they do one a bit cheaper.

Fraid not.

A friendly word with the parts desk may well get one on sale or return.

See my other posting re "cheap maintenance for BMW".

To cut a long story short, have you tried:

Opening the bonnet Looking for the fan "trumpet" connection (just under the windscreen) and unclipping it Reaching in and seeing if the fan has got stuck ... if so, see if you can free it with your hand!

So that was all that was wrong? How much did they charge for that?

For the group's info: Changed the final stage resistor - cheaper part from

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Job took 35 mins from start to finish, inc 15 mins locating it!

On RHD cars the resistor can indeed be located on the driver's side but it is on the LEFT of the pedals, high up behind the fan / aircon / radio control panel.

Incidently, I took readings of my new resistor and compared them to the faulty one.

Pins look like this

1 2 3 4 5

(my numbering scheme!!)

DIdn't measure all the pins but on the new resistor between pins

1 and 2 = 612 1 and 3 = 599 1 and 4 = 612 1 and 5 = 23

on the duff one:

1 and 2 = 135 1 and 3 = 73 1 and 4 = 136 1 and 5 = 50

all in Kohms

this *may* help someone trying to diagnose if their is duff

For that, and for replacing the pollen filters, which had got heavily gunked up, £45.

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