A/C clutch doesn't disengage

paclx · Apr 19, 2015

I recently recharged my A/C on my 97 P38 as it wasn't blowing cold after not being used during the winter, and the compressor wouldn't engage. There was still some gas inside the system according to the low pressure gauge, so I topped it up. I now have cool air, but noticed that (a) the low pressure pipes don't get really cold (visible moisture accumulation) and (b) the compressor clutch doesn't disengage. I've cleaned the connectors on the two switches to make sure they are getting good contact.

Any ideas??

Thanks.

Datatek · Apr 19, 2015

Yes, use the aircon all year round when it's fixed to stop things seizing up. It also keeps the interior dry thus protecting the BECM.
Does the clutch disengage when you press the off button? If not, check the relay if it's a post 98 car, for pre 98 check the output from the HEVAC,
Maybe just the compressor clutch has rusted due to lack of use.

paclx · Apr 20, 2015

Thanks Datatek. Yes, the clutch does disengage when the A/C OFF button is pressed.

Datatek · Apr 20, 2015

paclx said:
Thanks Datatek. Yes, the clutch does disengage when the A/C OFF button is pressed.

So relay or HEVAC output then.

wammers · Apr 20, 2015

If the aircon is turned on why would you want the compressor to disengage? If it disengages when aircon is turned off what is the problem?

paclx · Apr 20, 2015

i thought the compressor clutch cycled on and off during operation. is that not correct?

wammers · Apr 20, 2015

paclx said:
i thought the compressor clutch cycled on and off during operation. is that not correct?

No it runs constantly whilst the aircon is working. It will however cut off on refrigerant over pressure.

paclx · Apr 20, 2015

Thanks Warmers. I'll now drive with ease!

Datatek · Apr 20, 2015

wammers said:
No it runs constantly whilst the aircon is working. It will however cut off on refrigerant over pressure.

It cycles on mine except in very hot weather when it remains engaged most of the time. Easy to detect as you hear the engine note change as the clutch engages.

wammers · Apr 20, 2015

Datatek said:
It cycles on mine except in very hot weather when it remains engaged most of the time. Easy to detect as you hear the engine note change as the clutch engages.

Don't think it will be disengaging to often in Hong Kong.

Datatek · Apr 20, 2015

wammers said:
Don't think it will be disengaging to often in Hong Kong.

I missed the Hong Kong bit

paclx · Apr 21, 2015

Yes, Hong Kong. it's not so much the heat, though we are heading for the summer, it's the 95% humidity. Petrol is more expensive over here than UK, so I try not to use the A/C during the cooler months.

Datatek · Apr 21, 2015

paclx said:
Yes, Hong Kong. it's not so much the heat, though we are heading for the summer, it's the 95% humidity. Petrol is more expensive over here than UK, so I try not to use the A/C during the cooler months.

AC makes the best part of bugger all difference to fuel consumption on mine here in France in summer when it's mid 30's C, may be more noticeable where you are but id doubt it.

A/C clutch doesn't disengage

paclx

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Datatek

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paclx

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Datatek

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wammers

No longer with us, RIP

paclx

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wammers

No longer with us, RIP

paclx

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Datatek

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wammers

No longer with us, RIP

Datatek

Well-Known Member

paclx

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Datatek

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