C5 aircon pulley won't engage

[aramsay]

Hello.

I have an '02 C5 2.2HDi Estate, and the aircon doesn't work, as the electro-clutch on the compressor pulley won't engage.

On my car, it is a "normally on" system, and to switch it off, you press the "Eco" button on the cabin heater panel.

I checked the voltage at the yellow connector at the compressor, and get 7.9v on the live pin, but that is whether I have the Eco switched on or off.....

I've checked all the fuses that Haynes and the owner's handbook mention, and they are all OK.

Could there be a sticking relay somewhere ?

Suggestions please.......

Oh yeh....the system was recently recharged, and checked out with no leaks.

Slainte, Alan.

[addo]

This is switched by the BSI, there is a tiny solid state relay which may have burnt out. You can buy a replacement from Farnells but do need ability in soldering SMDs.

When fixed, install an external helper relay in the engine bay.

[aramsay]

This is switched by the BSI, there is a tiny solid state relay which may have burnt out. You can buy a replacement from Farnells but do need ability in soldering SMDs.

When fixed, install an external helper relay in the engine bay.

Do you know what location is of this relay on the BSi ?

Alternatively, I am thinking of temporarily just hard-wiring a wire to the socket to at least get it working. Do you happen to know the operating voltage of the electro-clutch ? Hopefully 12v......

Does it switch in and out automatically while aircon is "On", or is it engaged all the time ?

[addo]

The device is on the BSI "motherboard" or large circuit board. Pull the covers off, gently separate the two boards and look for a burnt chip near one corner, it's about 3/16 square.

Your compressor clutches in and out depending on the system load so it should only be bypassed for gassing a system pre-troubleshooting.

[addo]

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You need to be a member to enlarge the image, I think.

[aramsay]

The device is on the BSI "motherboard" or large circuit board. Pull the covers off, gently separate the two boards and look for a burnt chip near one corner, it's about 3/16 square.

OK, thanks.

Your compressor clutches in and out depending on the system load so it should only be bypassed for gassing a system pre-troubleshooting.

Hmm, yes I wondered.... Think that's a no-no for going on hols !

[KP]

That thread mentions a test to Initiate the clutch to engage for a few seconds but would you know where to find it in lexia at all Adam? Just to help me test one of my C5's?

[addo]

Some of what you can do, varies by model of car and diagnostic version. Look for actuator tests in either the BSI or if listed separately, climate module.

Parameters will show whether it's "seeing" the switch pressed or not.

[KP]

Cheers fella

Will give it a try soon when i next see the car