Technical Diesel Air Con Not Working

[NoahR]

Hi all,

Just bought a 2007 Fiat Ducato H/R MJ 120 2.3L (Not sure if there's other specific info needed?), and the air con doesn't work. The previous owner had it regassed a couple of years ago, and said it held pressure fine, but didn't work. - The light comes on, but the compressor doesn't kick in, and it doesn't blow cold.

I've powered the compressor directly with 12v from the battery, and the clutch kicks in. I've also checked the two fuses (both fine). I'm going to order a back probing set so I can back probe the three wires going into the pressure switch and read their voltage. I don't have any sort of scan tool for the vehicle, so I can't read pressures. I also can't work out where the relay is to check that. I expect it's an issue with the pressure switch, but I would like to be sure before I pay a garage to sort that.

Does anyone have any other suggestions on how to proceed?

Thank you

Noah

 

[NoahR]

I should add, I've check the voltage on the small red wire going to the compressor and I get nothing, so something stopping it.

 

[Mike1alike]

Yes, that's the way to go.
Relay should be in the engine bay fusebox.
And the pressure switch. On some Fiats you can see the AC pressure with MES so if you have MES, hook it up and check if it shows on yours. If it does and it reads it, sensor is ok, if it can't read it sensor is not ok.

 

[PuntoHowTo]

Did you get cold air if you power the compressor directly ?

Really while it might have been regassed a couple of years ago, if its not been used at all, or rather not worked since then its not unreasonable that the gas may have all leaked out again.

There is another post on here at the moment, someone with a 2006 van where the aircon evaporator probe (temp/frost sensor) has likely failed and this is preventing the AC from working.

 

[Communicator]

Did you get cold air if you power the compressor directly ?

Really while it might have been regassed a couple of years ago, if its not been used at all, or rather not worked since then its not unreasonable that the gas may have all leaked out again.

There is another post on here at the moment, someone with a 2006 van where the aircon evaporator probe (temp/frost sensor) has likely failed and this is preventing the AC from working.

The thread referred to above may be found here. As there are some similarities perhaps worth a browse?