Air con problem

[Ado1379]

Hi everyone. I have a 2.2 Z3 with aircon fitted, however it doesnt work.

I have just had the gas checked and topped up, and was told that it already had pressure in the system and just needed a little top up. So this doesnt scream leak to me.
The switch lights up when pressed but the clutch on the compressor doesnt engage. My old Z3 had the external fan come on also when the air con switch was pressed, this also doesnt happen on this one.

Has anyone got any ideas on where to check next? Ive never really troubleshooted an aircon system before.

 

[Rudyrov]

You can start by seeing if the system has pressure, most likely it does not. This might indicate a leak in the various pipes and seals.

 

[Ado1379]

The system was already holding pressure before i had it topped up

 

[Rudyrov]

see if the clutch on the pump works, could be that or the pressure switch in the line would be my guess.

 

[Ado1379]

So ive just found out my external fan is siezed. Not sure when that happened. Would a seized fan stop the aircon compressor engaging?

 

[Rudyrov]

Not sure but probably not. The fan comes on when you turn the AC system on but also the clutch gets energized so the compressor compresses the fluid and heat exchanging begins to happen.

 

[t-tony]

So ive just found out my external fan is siezed. Not sure when that happened. Would a seized fan stop the aircon compressor engaging?

No, it would not. Disconnect the wire to the compressor and see if you have 12v. with ignition on. If not get a jump wire from a 12v source and try feeding the wire which comes out of the compressor, by flashing a live wire to that contact you should see and hear the drive clutch engage on the end of the compressor. Another possibility is that the system pressure sensor has failed, this is what feeds the clutch magnet. I had this on my Audi A4.

Tony.

 

[Ado1379]

Thanks Tony, i'll check those today. Im hoping it not ths pressure sensor as it will need to be drained so i can change it.

Ill keep you updated

 

[Ado1379]

So Compressor runs when i bypass the supply. I take it this means pressure switch?

 

[Ado1379]

And the air is nice and cool so everything seems to be working.

 

[t-tony]

So Compressor runs when i bypass the supply. I take it this means pressure switch?

It looks that way.

Tony.

 

[Andyboy]

On some cars the pressure sensor screws into the condenser but as it's unscrewed, no gas escapes as it screws onto a Schrader valve.

 

[Mario]

On some cars the pressure sensor screws into the condenser but as it's unscrewed, no gas escapes as it screws onto a Schrader valve.

This is the case with the Z3 I know for a fact, with the standard dissicant filter