re: climate control

[Steve Valin <sjv@netapp.com>]

"Jevon B. Dade" <jdade@usibr01.usi.edu> asks:

<< I have an 88 90, and the knob for the fan speed ( I,II,III,IV) only
works 
on IV. I think that something in the switch is broken or dirty. I would 
like to get it fixed ASAP, so any help would be appreciated. >>

If your fan only works on IV, then it's likely the resistor pack. 
There's a device (pretty sure it's a diode) that appears to be the weak
point.  It eventually dies, thus opening the path thru the resistor
network.  I removed my res. network and crimped a 10A Schottkey barrier
diode (.3V dropout compare to .7 for silicon) in place of the failing
device.  Don't solder the fix in place - the resistors heat up, melt the
solder, and your fix falls out into the ductwork!  The resistor pack can
be found after removing the glove box. Look at the ductwork between the
blower motor and center console.  The resistor are in the ductwork
(where they get forced air over them).  You'll see the metal plate they
are mounted to.  A beefy 4 pin connector extends from the plate.  One
screw holds it in place.  It's an easy fix...

The reason that your fan works on IV is that this setting bypasses the
resistors!  

-steve

--
Steve Valin		sjv@netapp.com         408.367.3566