Heater and AC operation?

Finn · Oct 7, 2023

Hello.

Stupid question regarding AC and heater operation on a -95:

Is it so that when I turn the heater knob to floor/mix/windscreen (well, at least windscreen) it automatically switches AC compressor on as well?

So there is no way to just blow warm air to windscreen at all to windscreen without AC being on?

cobrajeff96 · Oct 7, 2023

Any time defroster vents gets activated so too does the A/C, and that's by design. OEMs figured most people don't use their A/C in the winter time which is actually a bad thing for the A/C system because the PAG oil inside the system doesn't get circulated which dries up all the seals in the compressor but also dries up the O-rings in just about every connection point. It's a good idea to run the A/C at least once a month.

Finn · Oct 8, 2023

OK, thanks for the clarification. Operation is perhaps not ideal for me but it is what it is.

maillemaker · Oct 8, 2023

Also it's more effective to blow dry air at the windscreen.

cobrajeff96 · Oct 8, 2023

It is ideal, actually, for that specific reason. Hunting down A/C system leaks are tough if the system isn't filled with UV dye, and usually by the time the owner addresses the problem (beginning of the hot weather) all the refrigerant and PAG has exited the system which makes dye tracing irrelevant. But even if there are A/C problems, the interior blower motor still activates.

maillemaker · Oct 8, 2023

I just bought a refrigerant detector and UV light kit.

Mustang5L5 · Oct 9, 2023

Modern A/C systems at least give you the option to turn the AC compressor on/off for any of the modes. Here, it's just AC, mix, and defrost that operate the AC by default. VENT and floor do not.

WHat's even more annoying for me is there is no option for VENT/Floor combined, as this would be a perfect setting for driving a convertible around in the fall.

I bought a refrigerant detector off ebay that has come in quite handy with other vehicles in terms of finding leaks

maillemaker · Oct 9, 2023

Mustang5L5 said:
Modern A/C systems at least give you the option to turn the AC compressor on/off for any of the modes. Here, it's just AC, mix, and defrost that operate the AC by default. VENT and floor do not.

WHat's even more annoying for me is there is no option for VENT/Floor combined, as this would be a perfect setting for driving a convertible around in the fall.

I bought a refrigerant detector off ebay that has come in quite handy with other vehicles in terms of finding leaks

Yeah I was noticing that yesterday as I switched between FLOOR and VENT.

What does MIX do?