HVAC unit problem:

[meck@postoffice.ptd.net (Michael Eck)]

Preston,

While troubleshooting why my fan wouldn't run, I can tell you to consider
two things:

1.  Make sure the control unit (if it's the digital unit) is sending the proper
    information to the fan control module.  There's a diagnostic that will tell
    about how much voltage the fan is supposed to be getting.  If you adjust the
    speed of the fan and run the diagnostic, that value should change.  If it
    doesn't, I would suspect the digital control unit is faulty.

2.  If the control unit checks out, the fan control module is a big integrated
    circuit on a heatsink located, I think, under the hood.  If you lift the
    plastic rain cover above the firewall (where you might access the actual
    blower itself) I think it's on the passenger side in there.  Anyways, that's
    what feeds voltage to the fan based on the information the digital control
    module sends.

I've got to say, you have a lucky problem.  The brushes on my blower are
shot.  I
have a replacement but no time right now to replace it.  I would rather have it
run all of the time that not run at all!  I just stick my thumb in every couple
weeks to assert pressure on the brushes and away it goes.

Hope this helps.

Michael Eck
86 5KCSTQ
88 GTI 16V