Hello Everyone, could do with a bit of help please.

 

Air con not been working for a few months on my Mk2 Octavia (no detectable cooling), I assume due to low gas levels (not been regassed since new as far as I know).Took to local garage - they added some gas, but main report was that 'compressor not working, only 5.5V on terminals when AC mode was ON.

 

Done some reading around this forum and early visual checking (without pulling anything apart yet). 

I'm sure the compressor shaft is spinning OK (no mag clutch on mk 2). No obvious issues seen at first inspection.

 

I'm suspecting that the fault is electrical - either the N280 solenoid/actuator on the compressor which regulates it's loading is either faulty, or (hopefully) there is cable fault somewhere on the feed to the 2-pin connector for the solenoid. Seems that chafed or corroded cables aren't uncommon, and might  explain the latter.

 

I'm aware that the Climatronic controls the N280 via a PWM signal, so I guess the voltage at the solenoid would increase as the current flow increases (to load the compressor), but I don't know if 5.5V should be sufficient to part load the compressor.  

 

Also, if a cable break or short I would have thought I wouldn't see any voltage at terminal, and I'm obviously getting some which seems strange.

 

Unfortunately I've not got access to VCDS to look at fault codes or compressor currents.

 

Any pointers gratefully received - I'm trying to eliminate simple faults before having to fork out £50 for a diagnosis, only to be told that I need to fork out a few hundred more for a new compressor, when that may not be the source of the problem.

 

Many Thanks, Matt.

Check the air con rad for holes. I need a new one on mine. Find a member near to you with vcds to scan for you.

Also the aircon does not work below 4c.

 

Any reputable garage doing the recharge does a vacuum check before adding new gas.

The tool used to recharge sucks out the remaining gas, weighs it and then applies a vacuum to the AC system, if it cannot hold this the system has a leak and the machine will stop and prompt the operator to abort or add UV dye and continue. If the process run to completion then there is no leak and the fault lies elsewhere.

 

If the car detects that the compressor is not working, it kills the power to the compressor. You could have a faulty compressor which is not unheard of on the MK2 Octavia.