i have a 1991 civic 1.5 dx. i had an electric problem and toke it to the dealer after i get my car notice that ac is always working even thermostat set on heat. it starts blowing hot and cools down really quick even the engine heat drops down.
why??

 

So, with your A/C button in the "off" position, your compressor clutch is still engaged?

 

Yes. Actually compressor kicks when I turn the fan on!!

 

Check the switch on the firewall that the slide connects to see if it moves when you slide the interior lever.

 

If you unplug the A/C thermostat or the A/C pressure switch, does the A/C still run?

 

I hate to ask, but is the AC button in the "off" position, meaning it is poking out and the blue light on the button is not lit?

 

Good point.

 

Compressor will run on defrost. If you mean it's just always blowing cold, move the temp back and forth and listen for the door to move, and you should feel the resistance. Do it kinda forceful

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