A/C compressor not kicking in..

[pontiff]

This doesn't necessarily have to be a 6n1 (pre update .. 1997 model) question but how does the AC compressor work from an electrical point of view?

I just bought (yet another) 6n1 polo however the AC does not work. The stickers on the rad support say it was serviced (I assume gassed) 12 months ago but when u turn on the AC the air doesn't go cold.

The switch on the dash lights up when selected, the 147 relay clicks into action (I removed then cover and confirmed) however I cannot hear the AC compressor clicking into action.


There is a simple 2 wire plug that goes to it so I assumed it was a simple case of 12v+ and - but there is nothing coming from the plug. The Haynes manual does not really have much detail on the A/C system let along wiring details so I'm not sure.

Any thoughts? Would that plug be 12v? I have checked all the fuses also and all appear to be okay . Everything else seems to work.

[Jmac]

6N1 and 6N2 has fuse links on top of the battery mate housed in their own sub fusebox. Check these, if ok check you actual have gas, pressure switch will stop feed to compressor if it drops below a certain pressure
Cheers
Jmac

[pontiff]

Thanks for the reply. I can see a 30 amp link under the clear plastic cover and that looks ok. This is an early 6n1, so doesn't have the larger box that the update ones on from later 97 have but I know what u mean.

If i energise the electric clutch manually (not the best I know) it does blow cold air so I can only assume that there is enough gas in it (will eventually take to mechanic to check for sure)

Il check elsawin and see if I can locate points to check and see where the voltage disappears.

[Jmac]

Ok if you did the clutch cut in manually then the comp is good and it should have enough gas but id still be checking just how much. Could also be a faulty pressure switch, faulty thermal switch, this one ive done before, its in the cooling system and switches the comp off when the engine gets too hot to take the load off the engine, its next to the ECU coolant sender. Should be black with a yellow ring round it. Next is a major culprit, is your thermo fans running ok when the ac is switched on?? the fan ecu control block controls this and the power feed to the comp also comes out of this mate. id be swapping one out to see if its that, grab the part number off it as some golf ones might be the same, im wrecking a Mk3 Golf at the moment
Cheers
Jmac

[pontiff]

Just checked car.. When the AC switch is activated the thermo fan comes on and goes off when it's 'off' so I assume the ECu is okay?

Found the yellow/black switch,it's a 4wire one yeah? I'll check on how to 'check' it when I get home.

I think I can hear the relay cut In them cut out again straight away, but I need to check a little further