Subject: Yes... Author: ejonesie22 : member since March, 2004 : 1068 posts Posted on: 2008-08-08 16:09:52

It is a two speed fan, with two sensors, a 99 degree C and a 91 degree C on the lower pass. side of radiator, above the lower hose outlet.

If it is coming on with AC, the sensor maybe shot, bet way to test is to jump the sensore wires and see if fan kicks on.

Like I said the sensors come in two different temp settings (for the low and high speed) they make a lower speed switch as well, a 82 degree C that lot of folks use in warmer areas. You take the 99 completely out, put the old 91 (or repalcement) in it's place then put the 82 where the 91 was. It brings the fan on sooner.

If the fan does not operate when the sensors are jumped, get the Electronics manual downloaded and trace the circuit.



Evan Jones
1984 733i(s) Polaris Metallic 224,000 Miles
1986 745i Bronzit 166,000 Miles
1984 745i Delphin Gray 148,000 Miles (in progress)
1979 733i back to life supporting the others

oh and a '73 Alfa Spider, just because...

• Engine cooling fan - bernas68 2008-08-08 14:32:27 (55 views)
  • Yes... - ejonesie22 2008-08-08 16:09:52 (44 views)
    • Thanks Evan, I'll check it and report back. ;) (nt) - bernas68 2008-08-08 16:17:38 (31 views)
      • Got it to work!!! :D - bernas68 2008-08-24 10:50:08 (19 views)
      • The aux fan with the two temp switches will not usually - kff 2008-08-08 16:49:54 (46 views)
        • I was thinking of another probable cause here... - bernas68 2008-08-09 08:34:17 (28 views)
          • Re: I was thinking of another probable cause here... - alexander 2008-08-09 16:53:00 (28 views)