Problem: Air conditioner starts working while its switch is off

Hi there,

I've just bought a secondhand 2000 Mazda 626 Lx in very good condition except for one odd problem: when I try to select the Defroster Air Flow mode (air towards the windshield) the air conditioner starts working by it-self, even if it's switch is off.

Any suggestion?

Best regards.

If you're defrosting, removing the humidity from the passenger compartment increases the ability of the defroster to do its work. It does this by design.

Most cars turn on the AC compressor any time "defrost" is selected. Helps to de-humidify the air and clear the fog quicker.

Of course the A/C won't run if the air coming into the evaporator is below freezing.

Auto manufacturers have seen fit to turn the AC on automatically when selecting 'defrost' to help clear the windshield.

If you check you will probably also find that you cannot select 'recirculate' while the defroster is on as well. That is usually OK with me, except when its very cold and I want the darn warmer inside air to go through the heater!

-DDave