So the weather is starting to get cooler and I am in need of my defrost in the morning only to find that I press the button, I get a light, but it doesn't switch from the vent position. No fuses are burnt out and I don't even hear anything trying to switch. Where do I start looking for the problem.is it the control modual in the dash or is it my heater box in the dash?

 

It could be the HVAC controls, the wiring, or the mode control motor.

Do you have a volt-ohm meter and know how to test for voltage and ground?

 

I have had a sim issue on my 95 - same gen as your 97. On mine I found that the "linkage" would bind up. I've been able to lube the linkage on the mode control motor and get it moving again. From the drivers side foot area, look up towards the center vents and you should see the motor and linkage.

 

Thanks for the quick reply. I will check that out today and see what i can figure out.