HVAC problems all of a sudden

[smtguy]

The HVAC was working fine until I had to go for a smog check. The guy left the engine idling for a while to get it hot enough to pass - it worked and my car passed the dreaded California Smog test. That was the good news.

The Bad News:
Since it has been warm here, I went to turn on the AC, but here is what I got:
-No blue light on the AC switch when depressed and no compressor or AC blower kicking in
-Heat coming into the footwells even with the rotary knob turned all the way to "blue" and bottom slider closed
-Heater blower working fine, and dumps more heat in the footwells if I turn up the fan speed - again slider is closed; ambient (outside) air coming through the dash vents.

I have checked the forum, but not seen anyone with any of these similar conditions. Have any of you guys seen this before?

Thanks in advance.

[marc79euro645]

sounds like a blown fuse

[smtguy]

Thats what i thought, but no fuses in the engine compartment were blown.
Thanks!

[86_6series]

Since the AC button doesn't light up when toggled, I would test the harness to see if you have juice to the switch.
If you have juice, I would jump the harness to see if the compressor fires up.
If there's no juice to the button switch, you may find the solution in the ETM.

I would start with page 157. 1985 is the earliest I could find, should be similar.

https://www.millerperformancecars.com/f ... Manual.pdf

[smtguy]

Thank you!

[smtguy]

Marc was correct - it was a blown fuse that I missed when checking the first time. Why it blew is a little concerning?
Thanks for the help guys.

[RossDinan6]

Unless a visual inspection shows the fuse to be vaporized, I always check with a meter. I have seen many a fuse look good and not be.

[smtguy]

Thanks Ross, yes, I always check with a meter.