A/C Corolla 2003

Hi and thanks in advance; I would like to how I can disable the a/c when selecting the defrost on the ventilation. (Corolla S 2003)

Toyota made it in a way that, whenever defrost is selected on the ventilation, the A/C starts intermittent without any control!!

If you start fooling around with bypassing the A/C you may void your warranty. The A/C compressor requires a 12 volt signal that engages the A/C.... what you can do is find the A/C compressor relay  or the wire itself and bypass this by cutting it and running a new wire intot he car with a switch that you can control the on and off of the A/C via the new switch. The target wire is a rest a ground and when activated is 12 volts.

Thank you Vel.

Do you have any idea where is located this wire??

Alex

Not sure where the wire is but look for the exhaust nipple for the compressor for the AC. There an input and output plug for filling the AC line with coolant and it's usually near the output.

The compressor doesn't cycle on and off when you have the temp set on hot, does it?

Yes it does

Alex

Toyota uses the A/C during defrost to blow dehumidified air on the inside of the windshield to help clear fog (i.e moisture).  If you have ever looked under your car during the summer after running the A/C you would see a puddle of water.  This water came from the air that is blown across the evaporator core and is then drained to the outside.  If you run the defrost with the heat selector towards the warm side, it will output warm air that has had the moisture removed.  The air travels over the evap core first then is routed through the heater core.  Look at page 127 of your owners manual for more info.

Hope this helps.