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Car A/C circuit, want to make manual control as it does not work properly.

apples

Jul 1, 2012
97
Joined
Jul 1, 2012
Messages
97
The A/C system in the car is as dodgey as a second hand lawn mower.

I would like to bypass the computer that controls it. I suspect a fault in the computer or a corroded, loose, wire or somewhere. I have also lost the central locking, the horn has blown a fuse, and the blower fan for the heater /ac has a mind of its own, turning on and off when it feels like it.

I figure I can rewire the AC compressor into a new circuit that will miss the computer. The one thing I am unsure about is the pressure switch that is on the top of the filter/dryer.

It detects if the pressure gets to high and then breaks the circuit to stop the compressor from pumping so the system does not blow up. Then again when the pressure lowers down it allows the compressor to start again.

I do not know what to do to detect when it needs to go on and off?
 

mrmodify

Feb 13, 2010
157
Joined
Feb 13, 2010
Messages
157
Need a little more info.

Evening Apples,

First what is the year make and brand of car.

Usually the switch on the filter/Accumalator is a low pressure switch. It is used to shut the compressor down when the low side pressure reaches about 10-20psig. this keeps the low side of the compressor from going into a vacuum and pulling air and contaiminates into the system.

The high pressure cut out switch is usually mounted on the compressor if it has one. Most vehicles don't..

It depends on the maker of the vehicle on how they control the temperture of the vehicle.

You will need to use a relays for the a/c clutch and the blower motor.

It is possible to do what you are trying to do.
 
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