Hi folks, great forum really helpful. 

I have a 2009, 1.2 petrol mk7 fiesta. The AC doesn't work even when topped up with refrigerant. 

The AC light comes on at the dashboard control knob. The radiator fan comes on and off when the AC is switched on. I don't know how relevant this is but at least one of the AC pipes is roasting when the car is on.

I had someone local come and top up refrigerant.. They were really decent filled it, identified it didnt work, removed the gas and walked away without charging me advising it could be an exoensive diagnostic journey possible uneconomical for the age of the car. 

Having researched, I asked the question if the magnetic cluth had disengaged when the system was full. It didn't. 

I am thinking flow sensor or compressor. Flow sensor seems worth a go at the price of the part but I take it I'd have to recharge the system to determine if that was actually the problem when switched on. 

My main issue currently is I can find nothing telling me where the AC flow sensor is. I believe there could be one or two (one each for low and high pressure). I can't see any and I'm really hoping it/they are not behind the dashboard. 

Any advice or assistance would be much appreciated. 

Many thanks 

Simon 

 

 

10 hours ago, ssm2200 said:

Any advice or assistance would be much appreciated...

Have you thought of taking it to a specialist A/C engineer, there are loads of them! If the guy was able to recover his gas, it certainly didn't leak out (so unlikely to be a condenser), and a used compressor on Ebay is very cheap.

He was my local mobile specialist AC engineer. It's s a 14 year old fiesta, I'm looking to do it myself or at least diagnose the fault myself to make it economically viable. 

I haven't tried testing for fault codes on Forscan yet will give that a go. It wss really location of the flow sensor I was struggling with, thanks

They are pressure switches, not flow sensors, which might be hindering your online searches.

On a Mk7 I think it'll either be mounted directly on the side of the condenser near the bottom, or on the accumulator in front of the wheel arch.  

Not the best photo but does that look like it? Seems to have been taped up previously 

17 minutes ago, ssm2200 said:

Not the best photo but does that look like it? Seems to have been taped up previously 

Yeah, that's it.  

See if you can get the tape off and check whether the plug may be broken, burnt or corroded inside.

That's the one that came off. i bought the car earlier this year for my daughter. I dont know the full history but that looks quite new to me, perhaps someone had similar idea before. I guess I'll need to re-gas and test. 

 

Does anyone know any other way to test if the compressor will even come on if sensor is bypassed? 

Can't really bypass the 3 pin pressure sensors like the old 2 pin switches.

*Edited*

Sorry, I've edited the post above to remove incorrect advice.

I'm not sure if there's any way to test the sensor without gas in the system.