Re: bmw-digest V9 #1180

["David L. Volkert" <dlvolkert@xxxxxxxxxxxxx>]

Paul -

I've got an '84, so I figure the technology on yours is the same. What I
found on mine is that after a certain amount of usage, the center vent
slider can cause you to lose cooling! What happens is, that slider has a
circuit board underneath it with a continuous contact to the slide from
about 10% open to 100% open. As you move the slider through that range, it
keeps contact with the circuit (keeps it closed) - that's how they enforce
having the vents open at least 10% before allowing the compressor to run.
After a while, the conductor on that board wears off. When I turned the AC
on, I would hit the switch and slide the control full open, and it would
work for a few minutes; but as I drove, vibration would inch the slider back
a fraction, into the "dead zone" and suddenly I had no cooling. Try pushing
the slider back to about 75% open and see if that corrects your problem. If
so, you can then consider whether you want to get a new circuit board (your
air flow will be slightly less, but compared to the cost of replacing the
unit, you may want to just live with it - it's not a DIY, IMHO).

David Volkert
Houston
84 325e (original owner, I might add)


> Original Message:
>
> Date: Wed, 04 Aug 1999 09:45:32 -0700
> From: Paul DeZan <dezan@domain.elided>
> Subject: Any E30 A/C experts out there?
>
> I have a bizarre intermittent A/C problem on my '88 325is...Dinan
> Engineering has told me to replace the dryer and the expansion valve,
> but I'm looking for a second opinion.
>
> Symptoms
>
> 1) When the A/C compressor button is depressed, cold air may or may not
> start blowing (usually it does).
>
> 2) After a short time (anywhere from 30 seconds to five minutes), cold
> air will stop blowing (that is, the fan keeps running but the air gets
> warm and humid).
>
> 3) Turning off the compressor for five or ten minutes, then switching
> back on will often provide cold air for another few minutes.
>
> 4) If the recirculation button is pressed while the system is blowing
> cold air, it will often extend the time the air remains cold - sometimes
> for hours.
>
> System is fully charged - no leaks. When it's working, the system blows
> ice cold air.
>
> Any thoughts?
>
> Thanks...pld
>

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