Hi all

Does the AC pressure switch screw on to a valve or does the gas need removing to change this.

 

TIA Colin

It's a sensor, not a switch, but yes, there's a valve under it.

Thank you

There will be a very slight loss of gas as you swap it out but if you do it promptly, it won't be much. I also believe there are two pressure switches, one on the low pressure and another on the high pressure. I can easily find my own low pressure one as its just near the coolant reservoir but I am unsure where the high one is. I think it depends on where the manufacturer deems it to be as I have read some can be actually bolted on to the compressor whilst others may be on the condenser.

No @mrgf, just the one pressure sensor (in the high side), no pressure switches.  The HVAC module uses the sensor readings to know what's going on and also to control the radiator fans.

 

 

 

Edited 3 August, 20214 yr by Wino

Oh, ok Wino... Thanks for that. On some looking at a/c in general, it was stated one on each high and low, so I bow to better knowledge. You do tend to know these cars well and as mentioned, I was generalising, from looking at some a/c posts on youtube, etc, not a Fabia, directly. 

By switch, I did mean sensor also, but often, its referred to as a switch. 

Edited 5 August, 20214 yr by mrgf

A pressure switch (which some earlier cars like Mk1 Octy had) has only two states, conducting or not conducting, so it only tells you whether something is above or below a given pressure. The Octy one is actually two switches in one package, one normally open, the other normally closed, not sure what their threshold pressures are.

 

A pressure sensor tells you more; what the actual pressure value is.