Climate control fan speed on '94 car

Just got my new (well 1994) car home - and wouldn't you know, one thing I forgot to test isn't working right - at least I don't think so. Turning the fan speed control up to 'almost full' is only resulting in weak airflow, you can hear the fan running but the speed is down, it doesn't even start to spin until past half way up the dial. Moving the control to the full extent kicks in 'emergency' mode just fine and it blows a gale at me. Using the temp dials seems to make hot and cooled air come out, but again the fan speed just rumbles along slowly.

Where should I check first? Does anyone know how the system works?

thanks,
james

to be fairly linear.It doesnt seem to vary its own speed.I would say you need to change your microfilter

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Originally Posted by system11

Turning the fan speed control up to 'almost full' is only resulting in weak airflow, you can hear the fan running but the speed is down, it doesn't even start to spin until past half way up the dial. Moving the control to the full extent kicks in 'emergency' mode just fine and it blows a gale at me. Using the temp dials seems to make hot and cooled air come out, but again the fan speed just rumbles along slowly.

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For reference (and I've booked it in at a local BMW specialist because they're cheap and I have to work during the day) - I noticed that sometimes it /does/ work properly - checked a few service bulletins and it seems thats a known fault with upgrade related to the resistor pack on the motor control.

If it is a resistor pack=relatively inexpensive, if "sword" resistor=expensive. Hope you have the resistor pack. I don't recall what the 540's had.

I noticed today for the first time that the fan speed does vary itself...I was parked in the garage and for some reason adjusted the temperature dial down with ignition on but engine not running . the fan speed increased.....this was with the fan speed of minimum just of the bottom of adjustable

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Originally Posted by Paul in NZ

I noticed today for the first time that the fan speed does vary itself...I was parked in the garage and for some reason adjusted the temperature dial down with ignition on but engine not running . the fan speed increased.....this was with the fan speed of minimum just of the bottom of adjustable

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Mine sometimes works when the car is cold, and then reverts to full extent on the adjustable equating to 'wind force of a butterfly'. It's a new enough car to be a resistor pack instead of the sword, symptoms seem to match so I'm cautiously hopeful. It doesn't matter how I set the temp. dials, it'll blow cold air extremely lightly, or hot air with the same power.

Quite gutted really that this problem (and the lighting one) have reared their ugly heads in just one day of ownership. About right for me - I could buy a brand new hammer and something would be wrong with it.

I know what you mean, my large radiator hose blew a leak right as I was driving it home for the first time. Had to get dirty fingers right away! If you check the Bentley manual, it should tell you which HVAC system you have and whether "pack" or "sword" is likely. The resistor pack is usually right above your knee under the panel on American cars. Bruno's site has good write-up on this one.

I have a '94 also. The resistor pack is nothing more than coils of wire having different resistance to change motor speed. No resistance at full fan speed because the resistors are bypassed. I fixed my resistor pack easily.
I found there is a copper rivet holding the pack together. Heat from the pack loosens the copper rivet. To fix, drill out the copper rivet, sand the contacts the rivet held together and replace with a small nut and bolt. Mine's worked like that for 5 years.

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Originally Posted by system11

Just got my new (well 1994) car home - and wouldn't you know, one thing I forgot to test isn't working right - at least I don't think so. Turning the fan speed control up to 'almost full' is only resulting in weak airflow, you can hear the fan running but the speed is down, it doesn't even start to spin until past half way up the dial. Moving the control to the full extent kicks in 'emergency' mode just fine and it blows a gale at me. Using the temp dials seems to make hot and cooled air come out, but again the fan speed just rumbles along slowly.

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An update - fixed now, thought my car was the resistor pack type, but that was me putting the wrong year into the ETK. Turns out it had the sword, and the sword was kaput - car dealer changed it.