cyfi66

I see this component in the Lexus factory service manual, but can't figure out how it works, what it does or why its there. Does anyone have any idea what its purpose is? Also the evaporator has 3 ports. A typical evaporator only has an inlet and an outlet, does anyone know what the third port is for? This is on a 1999 LS400.
Thanks

paulo57509

I believe it's supposed to keep the evaporator pressure from dropping below a pre-determined value. How it does this....?

99LSCHI

It prevents the evaporator from freezing from water condensation, will shut off the compressor if pressure drops too low or detects near freezing temperatures. As long as you see water coming from the drain line when your AC is on you almost never have to worry about this happening.

cyfi66

You guys are both referring to the EPR (evaporator pressure regulator) which is a separate component located in the engine bay on the suction line. Its purpose is to keep the evaporator above the freezing point so that the evap doesn't ice over and also makes it so the compressor doesn't have to cycle to maintain the evap temperature above freezing. Below is the evaporator pressure regulator (different component than the one I am asking about).

The "pressure regulator" in my original post looks to be on the inlet to the evaporator and is a completely separate component.