I'm adding some notes to Chris Blumenthal's excellent FAQ article http://www.bmw2002faq.com/content/view/73/32/


1) I have confirmed that the new replacement Behr heater fan with Bosch motor (made in Spain) has reverse polarity as compared to the original Bosch German motors. Looking at the motor with the (2) terminals facing you, the left-hand (Male spade) is negative (-) and the right-hand (Female) is positive (+). While "bench testing", I connected my new fan up to the original wires (red + from left-side of the resistor board and brown - from the right-side of the resistor board) and it turned backwards, blowing air out of the box.

2) The fan blades may be slightly different on the new assembly, which may interfere with both the plastic cage and fresh air flap (when fully opened). I'm having trouble getting clearance after multiple "adjustments" to the blades.

3) The red plastic bushings that secure the fan to the motor shaft may push apart from each other, causing the fan to become wobbly (See note 2). Make sure they are pushed up tight against the fan.

4) When re-installing the top cover (with fan) to the main housing, leave the (2) large heater core tube grommits off until you have positioned the top onto the box. I found this method is much easier. To fit the large grommits, start by fitting them at a sharp angle to the cover, then use a small flat-blade screwdriver to carefully work them into place. New seals are definitely needed when you are re-doing your heater.

4a) Pre-fit the small grommit for the heater valve in the cover, then fish the cable thru the grommit while tilting the cover down into place.

5) Instead of using rivets to hold the top cover to the box, I purchased some brass hardware from Lowes'. I got this idea from Keith Kreeger's website.

Here is what I used:
(6) 10-24 x 1/2" long round slotted machine bolts
(12) #14S flat washers (above and below the box)
(6) 10-24 nuts

6) Instead of using foam weatherstripping on the cover to body, I'm going to use EDPM Rubber weatherseal ($ 6.28 from Lowes'). MD # 63669 5/16" x 19/32" x 10'

See my pictures - hope this is helpful to someone.
_________________
Jim Gerock
BMWCCA # 381868
73tii "Celeste" # 2764081
71 VW Cal-look Bug


Last edited by jgerock on 3-14-09 12:51; edited 1 time in total