This sound like AC pressure switch to you?

[jeff33702]

AC hasn't been especially cold so I bought one of those cans that everyone uses (Used it on our Tacoma and Mustang and it was awesome). Charged it up to the blue, like it says...just took a little..maybe less than half the can. AC pumping cold as can be for a couple days. Today, drove the guys to lunch and it was pumping warm...nothing. Turned the car off and back on, ice cold. After work it was warm...now it will not get cold at all. I don't think the compressor is running. There is pressure in the system...in fact, now the gauge from the can/kit says the pressure is in the red. I'm guessing that might equalize if/when the compressor comes back on?

Any ideas?

[Audibot]

Is your ECON light showing?

Could be a pressure switch. Would be safer to have someone with VCDS check it out, but if you remove the front bumper, the A/C pressure switch is right there. A few years back I found the O-Ring on my had gone and left it with a dirty, oily mess.

[dtoys4.2]

I replaced my switch without removing the complete bumper. loosened up the driver side and pulled it forward. u don't need a whole lot of room to get it out

[jeff33702]

https://www.youtube.com/watch?v=r2fW_XCAu1I

This guy mentions these control valves. Possibility?

[jeff33702]

Where exactly is the pressure switch located on the RS4? Have bumper off... I'm probably looking right at it.

[jeff33702]

I found it. Duh. There are 3 conductors. Does anyone know which ones to connect together to bypass? I'd like to see if the compressor kicks on before I go buy a $75 switch.

Thanks

edit: occurred to me that it's probably a reference signal and ECU reads it...so maybe cant simply jump it.

[jeff33702]

Ok - so I swapped the pressure switch and had a bud evac and charge the system. It's still hot. The compressor is not turning on from what I can tell.

Any ideas? It's getting hot as hell here. I'm going to get it scanned on Saturday but just hoping for something else I can easily check.

Again - went like this: Noon - start car, it's warm. Turn car off and back on, it's ice cold. Afternoon, nothing.

Would the http://www.amazon.com/URO-Parts-4B0-...ords=4B0820539 cause the compressor not to turn on even if the AC was set to LO? (LO is ON, no matter what, right?).

[Audibot]

It's possible OP. The only other things I can really think of would be the orifice tube being blocked somehow, or too much oil in the compressor.