HVAC unit problem:

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

The diagnostic mode is accessed by holding the outside temp button and pressing
the off button.  The warm button is used to move up through the diagnostic
channels, the cool button displays the value of the channel.

Since you removed the digital control unit, it's got to be that fan control
unit under the hood.  Someone, a few messages back, left a part number and
some more info.

Michael Eck
86 5KCSTQ
88 GTI 16V