Hi folks, Ive had a look through the past posts on this but cant find anything to match.

Climate control attempts to engage the clutch but does not, and 'cycles' between this when the AUTO button is pressed. The system was topped up about a year ago to full (still had 650 in out of 750 when started).

The clutch and nut are still fully in place

No fault codes

Fuses on top of the battery are OK

Any thoughts?

Cheers!

Sounds like the clutch is about to die. Have you tried slackening off the aux belt and seeing if it operates then? May give a clue as to whether it is a dead clutch.

You could also try getting a multimeter and seeing if that is all ok? I believe the wires can perish on top of the unit and somewhere under the car.

When I was trying to fix mine I found rebuild kits available but it involves removing the compressor IIRC. No point in buying a 2nd hand compressor if its not been refurbished as you may have the same trouble 6 months down the line.

Check the voltage at the 2-pin connector on the compressor.

It's very common to have a problem at the 4-pin connector that slots into a bracket on the starter motor. The other two wires go the alternator.

Guy reckoned it was possibly the low pressure switch not allowing the compressor/clutch to do its thing properly (poss lack of gas)?

Its going in on Saturday to an aircon specialists for a looksie. He reckons the compressor is OK.

Edited 6 November, 201213 yr by Liverpool-Lad

If it was the HPLP switch it wouldn't even attempt engaging the clutch...

Unless of course the switch is faulty? I sourced a replacement switch from ECP for less than £20 with brisky discount...

OK So Ive had some checks done on the system, the gas was recovered and put back to the full 750g. The HVAC system was checked for faults with no issues. Still doesnt engage.

So its either an electrical issue or the compressor clutch. Guy advised me to go to an auto elec and bypass the pressure switch and see if the compressor comes on. Is this easy to do myself? I tried unplugging the compressor connector (2 wire) but couldnt get it off - to see if i could get a voltage from the plug.

Tried pressing the multimeter pins into the connector but couldnt find a voltage. Either that or i wasnt hitting the connector properly.

Edited 11 November, 201213 yr by Liverpool-Lad

At the 4-pin connector (see post #3), the green/black and brown/black wires go to the a/c magnetic clutch.

Disconnect and measure the voltage on the fan controller side and the resistance on the a/c compressor side.

Thanks, is it accessible from the top of the engine bay?

How does the clip also come free from the compressor?

Edited 11 November, 201213 yr by Liverpool-Lad

Found the clip but cant prise it apart. Grr!

Thanks, is it accessible from the top of the engine bay?

How does the clip also come free from the compressor?

Yes, it's just above the starter motor. If in doubt, follow the thick alternator cable from the battery until you see the 4 wires attached to it. Follow the wires back until you reach the connector.

IIRC, there are two different types of connectors on the a/c compressor. The small square one just pulls out. The larger rounded type opens as described in http://www.briskoda....s/#entry2285681

Thanks. The plot thickens. At the starter block connector Im seeing a slight varying voltage anywhere between 4-6 volts. Same at the air con compressor 2 pin plug.

This probably explains why it hasnt enough voltage to start properly.

Any thoughts?

I should say as well the twin fans do not engage either

With the blower on 1, does the yellow light on the a/c switch come on?

Its climatronic Thinking of going for the fan control module?

Edited 11 November, 201213 yr by Liverpool-Lad

I'll check the schematics tomorrow and post some more things for you to test.

Thanks for your help, much appreciated.

Found this too but its a bit out of my depth. http://www.justanswer.com/vw-volkswagen/2d98w-2004-vw-golf-air-conditioner-compressor-does-not-engage.html

Edited 11 November, 201213 yr by Liverpool-Lad

IIRC there's a module under the battery tray that can get corroded.

Is your HPLP switch 3 or 4 pin? If its 4 pin you can bypass it, if its 3 pin then... you can't. Also, check the fuses, I can't remember what they are exactly but there's 2 or 3 to check.

IIRC there's a module under the battery tray that can get corroded.

Is your HPLP switch 3 or 4 pin? If its 4 pin you can bypass it, if its 3 pin then... you can't. Also, check the fuses, I can't remember what they are exactly but there's 2 or 3 to check.

It's the fan controller, but it also controls the magnetic clutch. There are two basic variants - one has 10 pins and the other has 14 pins.

The fan control unit is fed by two of the fuses on top of the battery - the third of the bolt down fuse links and the green fuse nearest to them.

Hi, just read up on that one. Large flat fuses look to be fine plus the smaller green ones are OK too.

I have looked at the fan controller being suspect too. Im guessing this module will control and give full voltage to the compressor too. Odd how Im only getting approx half of the full 12v to the compressor.

Tempted just to get a new fan controller at this point and go from there.

Edited 11 November, 201213 yr by Liverpool-Lad

You have the 14-pin version of the fan controller. Follow the radiator fan cables back through the connectors and you will find the fan controller. There is also a 4-pin, high current connector. Your system has a pressure sensor and not a pressure switch.

Check fuses F5 and F16 in the main fusebox.

If you have VCDS, check for faults stored in Climatronic. If you don't have VCDS, follow the instructions in thread http://www.briskoda.net/forums/topic/209451-climatronic-self-diagnose-mode/

Check power and ground first.

On the large 4-pin connector, check you have 12V at pins 1 and 3.

The earth for the fan controller is under the battery tray and is prone to corrosion.

On the 14-pin connector, check you have 12V at pins 4 and 9 - earth at pin 6

Thanks. I have ordered a new control module which was £30 new OEM. I will check the wiring voltages too as mentioned plus the earth.

There was a HVAC error code but only an internal flap motor error which I knew about anwyay.

Cheers

BTW, neither of my fans ran either but it wasn't the fan module at fault, it was the HPLP switch!

What happened to your compressor clutch when the AC was on ?

Where is the HPLP switch too for ref - further down from the compressor near the crank pulley ? Ta!

HPLP switch is at the back of the engine on the firewall in the middle, it will be wrapped in a silver heat resistant cover. Mine didn't run at all but I replaced the HPLP switch when fault finding, it didn't turn out to be the problem though.

Not saying it is, but a faulty switch may cause problems!