I think the problem lies in the low voltage coming out the sensor. The trick is to get the voltage in the middle.

How To Bypass Lo Pressure Switch For Ac Jeep Cherokee Forum
How to jump a ac low pressure switch 3 wire. You can jump three wire ac pressure switch to control the ac system as well. Ive tested the voltage on the signal wire at the ecu and got 02v with engine running and ac on. How to jump 3 wire ac pressure switch. I used 2x 2k resistors one from 5v to middle and one from gnd to middle. So ive sent him back to the place that regassed the ac to have it pressure checked. Shorting the green wire to 5v or 0v would be sending voltages that would indicate to the ecu either extreme low pressure or extreme high pressure.
Maybe they just told him. It does the process by monitoring fan operation high pressure and low pressure then sending the information back to the computer for it to analyze. You might have to do some repairs by yourself to make it run correctly again. If you jump the low pressure switch with the engine running do it only for a few seconds. You have to make sure that the compressor has enough oil to function properly. Amazon link ac relays toyota httpsamznto2nabjbn if your ac compressor clutch wont engage because the refrigerant is too low then you can jump the 30 and 87 pins to get the clutch engage.
Which wires do you jump around to get current to the clutch so i can add enough freon to get the low pressure switch to allow current to the clutch. Do not jump the low pressure switch to operate the compressor non stop so you can add refrigerant. The three wire switches is also called as pressure transducers. My 03 jetta has a three wire plug pressure switch on the large line close to the firewall. Check the pressure of the air conditioning system by attaching a low pressure gauge from a refrigerant recharge kit to the low pressure fitting located between the accumulator and the compressor and marked with a capital l according to aa1 car on an 80 degree day the low pressure gauge should measure 56 psi pounds per square inch or higher. Low ac pressure will prevent the relay from sending power to the ac compressor clutch.
The ac runs perfectly but you cannot control it with the button. These are used with gm variable control compressors and displacement compressors. Jump the low pressure switch only to test the circuit. Ac systems in vehicles run with a pressure switch. In a few car models the power of the air conditioning system flows from the ac switch to the fuse before being transmitted to the clutch oil through the low pressure evaporator temperature. Maybe they filled it and didnt check for leaks.
Jump power from battery oil charge mechanic how ac system works. Ac compressor ac condenser r134 2008 nissan altima to 2012 nissan altima. One might wonder how to jump 3 wire ac pressure switch by own.