Date:         Mon, 6 Jan 1997 08:00:34 -0700
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         "Michael A. Radtke" <m.radtke@elm.az05.bull.com>
Subject:      Heater Blower Resistor Replacement

Hello,

My 1st and 2nd speed front heater blower speeds have quit working.  Looking 
at Bentley, the most likely reason seems to be the one common fan motor 
resistor.  Nothing in Bentley says where this resistor is, but after a 
quick look at the dash wiring, I conclude that this resistor is actually in 
the fan housing.  From other posts on the list I see that this is not a 
good thing because of the difficulty of access.

However, the wires that the resistors bridge are easy to access.  My first 
thought was to just replace the resistor externally.  However, this 
resistor must dissipate about 60 watts so cooling it or keeping it from 
damaging other under dash stuff by its heat may be a problem.  So, it then 
occurred to me that perhaps an electronic pulse width type speed control 
might be a better idea since it would dissipate very little energy.  (I 
believe that some cars use this technique, especially those with 
continuously variable speed blowers.)

So my questions:

1) Am I correct about the resistor location?

2) Has anyone else tried an electronic substitution?

   a) Did you build it yourself?

      A) May I have the circuit?

      B) Any warnings or advice?

   b) If you bought a solution:

      A) What did you buy?

      B) Where did you get it?

      C) Cost?

Thanks,
Mike


Michael A. Radtke  -  Z74               Voice: 602-862-4897
Bull                                      FAX:         4853
13430 N. Black Canyon Hwy.
Phoenix, AZ  85029                      Email: m.radtke@bull.com