HELP! '86 5ks blower stuff

["Ken Keith" <auditude@impulsedata.net>]

If someone could help me out, I would appreciate it.

As I type this, a coworker or mine has his dash apart, and is trying to 
replace his blower motor.  He's got a question regarding the "a/c blower 
control unit".  It has 4 wires coming from it (apparently: power, ground, 
motor, control module).

The new motor works when he applies voltage directly across it, and the 
control head (that GM part) was supposedly tested by a mechanic and works.

This a/c blower control unit has heat sinks, BTW.

Basically, he wants to know what the function of this thing is, so he can 
figure out why it's not working.  (The blower doesn't blow when he tests 
it)

So, if someone could respond to me directly, I can call him at home and 
let him know.

Thanks,

Ken