A/C Blower Motor Speed--'84 633csi

[BRAlbright@xxxxxxx]

I purchased an '84 633csi last year from the original owner.  At that time 
time, the fresh air blower motor only worked at high speed, but the A/C motor 
worked proportionally.  Recently, both motors would only work in the high 
speed mode...

So, I purchased a new transistor (P/N  64-11-1-381-784) and (searching high 
and low) replaced a transistor located behind the fresh air blower motor.  
Now, the fresh air motor works proportionally and the A/C motor still works 
only in the high speed mode.

Is there a second transistor for the A/C motor?  OR is there another 
electrical issue?  If there is a second transistor, where would it be? (I 
currently have the Bentley 5-series manual and the Chilton BMW manual)

What other vehicle does this HVAC system exist in (the E28 is far from 
similar)?

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