I have just fitted genuine resistor back, cleared fault codes and what she keeps displaying now are: 313, 314, 315 (only). I removed the controller and I am going to take it to wrecker and ask for the same, unless there is some reasonably easy trick to inspect-diagnose the controller ?

 

No real way to test that I know of except to swap into a known working car.

 

I'm having the same problem (manual A/C).... the first 3 speeds have been working (but not he 4th), fuses are good, the A/C compressor runs and you can hear the recirc flap opening and closing when you move the switch, but now cabin fan.

Is the blower behind the glove box, or do I need to remove the dash (again)...

Is there a good diagram somewhere to test the switch? or to check if I'm getting power to the switch?

I'm going to pull the glove box today and see if I can get oriented and hopefully I can troubleshoot without pulling the dash.

John S.

'93 850GLT