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Bring back Fraggle Rock..
410 Posts
Discussion Starter · #1 · (Edited)
Well, I've been having a problem with the new car (E46) since I bought it, in that the fan seems to have a mind of it's own and will go to full speed while on any speed setting. It seems to be a common fault and is more than likely caused by a faulty final stage resistor. I replaced this yesterday (GSF - €75)and am happy to say that the fan functions perfectly!

You will need:
-Phillips screwdriver
-Torx 20
-Final stage resistor (GSF P/N: B93499) (BMW P/N: 64118385549) as shown below:
-Patience of a saint.
-To see a Chiropractor afterwards.

Remove the drivers side under dash cover (3 philips screws and fastener to center console) and disconnect any wires for the attached light and speaker. Looking from the side in towards back of centre console you will see a black plastic motor bracket (You may need to hold vent duct out of the way!) There should be 2 obvious connectors, one for the resistor which you should recognise by the silver heatsink partially visable, and one for the motor. The motor will unclip and with it out of the way, you can remove the two torx screws holding motor bracket as pictured below.

Remove the motor housing, you will need to disonnect the linkage from the top. The resistor should be clearly in view, remove the connector (now is a good time to plug in the replacement unit to test before final installation) remove two more torx screws and release the main clip holding it in. Slot in the new one and resecure (a bit of blue tack on the end of the screwdriver will help as it's easy to lose the screws when reffitting!). When reassembling, make sure the linkage on the motor bracket is secured back correctly, the top of the motor has a slot that fits into the linkage only one way, so you may need to turn linkage a bit for the motor to sit fully in. Resecure the bracket, refit the under dash cover and you are sorted! :cool:

(Photos courtesy of E46 Fanatics)

My car is a 2001 RH 325i automatic. Recently the blower motor ceased to work. I read about the final stage resistor problems on this forum and decided to replace it. From my experience I would make the following comments:

The major difficulty in replacing this item is the removal of the servo motor and mounting. While it is essential to remove the motor it is not necessary to disconnect the servo linkage. The top Torx retaining screw, as shown in the second picture, elsewhere in this thread, is a total B**** a) to see and b) to remove. With the servo mounting unscrewed it may be pushed out of the way while the servo arm remains connected. The final resistor unit in my car was retained only by a vertical plastic clip; and once unclipped the unit could be pulled out with reasonable force.

To facilitate replacement the original top Torx screw it should have a long shank welded to the head. With the faulty final resistor unit removed, the electric plug was re-inserted and the blower motor re-tested. Nothing happened. However inadvertently the heat sink spines touched the earthed metal of the steering column. The blower motor instantly started working (spines not earthed). While I have replaced the unit, just to be safe, I think there is some evidence that the problem with these units lies with corroded connection terminals. Others may want to examine their connection for corrosion before replacing the unit.

Keep it clean
2,495 Posts
Did this today, and by lord its right at the top of my worst jobs to do, followed closely by the PCV valve.

The top bolt of the servo housing is a bloody nightmare.

It is achievable so patience is the key. Also the pest position is to kneel on the ground so your 2 hands are free to A) twist the Torx driver and B) use the other hand to guide the end of the driver.

this is not a joke , visualisation is the key as you really can see the screw and also you fingers cannot touch it.

Anyway job done and lovely cool cool air blowing on my face. :cool:

1 Posts
Completed this job over the weekend - paying for it with neck and shoulder pain.

My fan speed was hunting up and down like it couldn't make it's mind up; not much but just enough to wind me up. The change seems to have done the trick.

Like Portiadog, I left the motor arm connected and there were no screws holding the resistor in place - just a tight fit around its housing and the plastic clip. Screws must have been optional! I located a pair of suitably sized self tappers and used them to hold the new part in.

My gripes were also with the top Torx screw on the motor housing. I found that you could just see it with one eye if you squeezed your head up in the recess next to the steering column. I did, however, waste a lot of time trying to undo it with a 1/4" ratchet and bit set, only to find that the bit holder was too big to allow the bit into the screw recess. My Torx screwdriver was too long due to the steering column so I modified it by snapping the handle off - perfect.

A final point I'll make is that when reassembling the motor housing I put the top screw into its hole first, held it in place with the screwdriver, which I held with my left hand, and then with my right index finger I could hold the sharp end of the screw and guide it towards its hole. I got the screw started and then with a bit of effort the guide on the top face of the housing could be mated with its partner on the body and then the second screw put in. All this was done whilst upside down with my feet on the headrest. About 3.5 hours all told but it would definitely be quicker second time around.
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