Got a different one for ya. A/C wont turn off.

[govbrown]

It's the exact opposite of most people's problems. I got A/C working in my 88t and it blows ice cold out the vents during the hot summer months. Problem is, I got off work this morning, kinda chilly out, turn the digital HVAC to 90. Ice cold air coming out. I pop the hood, compressor is still engaged and spinning away. If I turn it off completely, the compressor disengages and I get hot air seeping through the vent as I drive.

What's my issue? I'm leaning towards the temp sensors in the car not reading the right temperature. Can I check that in the HVAC diagnostics? If it comes down to frosted windshields before I fix this issue, I'll just unplug the ground running to the compressor.

[Z_Karma]

I believe the A/C compressor runs when the heat is on to dry the air.

Maybe it's also possible you have a leaking actuator diaphragm that's not opening the right vent door. I've had that too. I doubt that the in-vent thermistors are going bad, they're just passive resistors.

I've heard however that the headunit can suffer the same electronic gremlins that plague other electronic components (dry caps/failed solder joints). I've been through 3 of them in my 84T. All with different failure modes.

[govbrown]

I went through and tested the diaphragms when I had the box out this summer. Unless it was between then and now (wouldn't be surprised), they aren't leaking.

I do have a buddy with an 85T with digi gauges and can pull his unit and pop it in to see if it works. I'll check in to that.

[badq45t]

The AC turns on when you run the defoster not the heat. There is a switch that kicks on when you have want the compressor to turn on. If you unit is a digital dash that is bulit into the automatic system so more than likely the advise you got to replace the unit is best bet. If you have analog there is a switch that might be bad.