Aircon does not run cold on V6

[Mrs Feynmans Bongos]

Would be very grateful for some help, suggestions please

AC Compressor pump on my V6 started grinding.intermittently, after hitting a pothole.

Garage removed the original AC pump with bare wire into its clutch solenoid. So it sounds like the connector was pulled off before (the need to unplug) it was noticed

AC pump was replaced (after fun getting variant with the right pipe inlets), system regassed.

But it only blows does not run cold, EXCEPT when 12V is briefly applied "manually" to the AC solenoid (not from the dashboard temperature control ?ECU or Relay)

From
https://igmaynard.co.uk/bongo/forum/vie ... or#p715465 I see the following are relevant to the AC:
- 30A PAL fuse in X02 box mid-bonnet
- 2x 10A mini fuses, UL, LR in X03 box, drivers footwell
- 2nd relay from front, nearside wing (under coolant tank)
- ECU? generating "cold demand" signal to AC solenoid.

Garage tells me they have checked these fuses and relay, but had to replace a melted fuse in the X01 box (battery).

I am wondering if rough removal of the failing AC pump damaged/broke the solenoid connectivity upstream, not just at the pump connector. If this was done under power, perhaps it caused a damaging spike to the temperature controller ?ECU. This might explain why the AC/2nd Relay can be manually switched but no "cold" results (if proven)

What should be done next?
Is the loom upstream of the AC solenoid easy to get at?
Garage is stuck so I'm getting desperate.

Please help

[g8dhe]

The normal procedure is to locate whether the electromagnetic clutch is pulling in on the pump, it sounds like it isn't.
So start by checking that there is power at the plug to the compressor itself when the clutch should be operated, if not then check the power at various points back up the chain G3-02 relay, via the controller and the two fuses to find out where its failed.

[Mrs Feynmans Bongos]

Thanks Geoff

Ok I have found the AC circuit you posted viewtopic.php?p=723668&hilit=Chinese+based+one#p720503 (may even be able to view that with Flash in Chinese browser).

Not sure what you mean by "pulling in on the pump"?

Will ask again, but garage tells me AC BLASTS COLD when 12V is touched briefly onto the electromagnetic clutch signal line into the AC Compressor (disconnected from the loom for this test).

Doesn't that also show AC must have its fused power ok?

Doesn't that test show AC "demand" signal is not getting through, from the dashboard? Is that "demand" signal what you mean by "back up the chain G3-02 relay, via the controller"?

[g8dhe]

The pump has a pulley which is turned all the time by a belt from the engine itself.
However to connect the pulley to the pump there is an electromagnetic clutch which needs 12v applied to it to engage.
Your write-up suggests that this works when the power is applied directly/manually.
So check what is happening yourself, measure the voltage at the connector to the clutch.
Operate the relay by turning the power on - do you feel the the relay click when you put your hand on it ? Does a voltage appear at the connector ?
If not then check the relay itself, maybe its damaged? Check the wiring from connector to relay with a meter ? Check the fuses with a meter ?
If you garage can't do this than either check this yourself or take it to an automotive electrician to sort out.

[Mrs Feynmans Bongos]

I'm very relieved to say the garage boss had another go today, solved it, he writes "was a bad connection on the relay underneath the fuse box".

Not sure which one he means, guess I'm not bothered now it's blasting out COLD air! Not pressing the point, but seems to me consistent with my "stress on loom due to rough extraction of old compressor" theory.

Very grateful yet again to Geoff for advising about this.

[g8dhe]

Yup there are relays situated on both wings and down underneath the starter battery in this case the one marked G3-02 sounds like it has had the wiring pulled or the relay itself disturbed;