Disable A/C when defrost is on?

[gbell210]

I have a 2000 corolla VE and I was wondering if anyone knows how to disable the A/C from coming on when I set the vent selector to defrost. I know the newer cars do it automatically, and I understand it clears the windsheild faster. But with the A/C on it also put more load on the engine (i.e. uses more gas), and in my older toyotas I just put the regular outside vent on and it keeps it clear most times.

I was wondering if there is a wire that tells the A/C to turn on when in the defrost position. If so, I could just disconnect that and the A/C won't get the signal? Or is there more to it then that? I don't have a wiring diagram , but I really would like total control over if the A/C is on or off in all vent settings.

[Flashmn]

Defroster turns on the AC, because it gets rid of moisture in the air. I think 2000 corolla is already electronic and no wires.

[diver9000]

Look up Dr. Tweak -- www.phoenixtuning.com and ask him this question. He is really good with this sort of thing.

[gbell210]

I know it gets rid of moisture in the air, but if you keep a constant flow across the windsheild of outside air, it does just as well "most" times. The A/C just makes it pretty much instantly disappear, so it doesn't need to always be running. (at least thats how I feel)

[Flashmn]

Only way to do it as I would see is to hard wire switch at the AC relay, so that the magnetic clutch doesnt engage.

[cam76034]

It is recommended to run the AC at least once a week to ensure circulation of the oil througout your system to keep seals and rings lubricated. Trust me, I just replaced a compressor that the seals had dried up on from not being used (from up north)

[retiredat44]

If i were you I would leave it alone. Defrosting works much much better with a/c anyways and running it every now and than is good.

[diver9000]

I know a lot of the newer cars are that same way. You dont have a choice in it. Its most likely wired into the A/C amplifier so anytime you put it in defrost mode the compressor is engaged, but you control the temp. You can leave your outside/recirculate switch set for outside air and leave the location switch in defrost but leave the fan switch off and it shoud still blow some hot air without engaging your compressor.

[toyotaspeed90]

but when you are defrosting the a/c doesn't stay on.... it will generally turn on and off periodically..... the increase of gas consumption is pretty much negligible..... keep your foot out of the gas, replace your O2 sensor, your air filter, and your spark plugs and you'll see a MUCH better gain than going at this.....

[hilux5084]

It is better to leave as is the other advanage to the defrost is the compresor seal is moisened to help prevent refrigerant leakage in the colder seasons.
Joe