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Feb 10, 2021, 08:44 AM#14
i replaced my dodgy blower motor yesterday and all is working accept the AC , the clutch is not engaging . i have put power to the clutch and it works just not kicking in .is there a main conspirator for this or is it a case of just keep looking , which relays run the clutch , where dose it get power from and what stops it from working . (97 gems)
PS it has worked before, that's the clutch not the AC , as i have seen the clutch kick in but i don't know if the actual system worked as i thought it was the blower that was stopping the system from working. never really had AC as the rest of the system had its own problems but its all good now just no AC.
nano alarm reads (33) compressor clutch circuit open .(fault type= current)
this is the first time this fault has come up , normally blend motors or fans, but they are all fixed now
where would be a start point for this issue , any ideas , thanks in advance.

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Feb 10, 2021, 09:09 AM#16
i did have the system checked a while ago and the man said it had refrigerant in it but their was other problems , air gap was to wide the fan relays etc and left it at that . i now think i have fixed all the other things just the AC to go

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The Nano is telling you the fault. On a GEMS power comes from the HEVAC,through the multiway connector behind the RH kick panel to the pressure switch (which is only closed if there is pressure in the AC refrigerant circuit) and on to the compressor clutch. So it can be a poor connection in the kick panel connector, a dirty connection in the plug onto the pressure switch or you just haven't got any refrigerant in it. HEVAC detects how much current is flowing and if less that it expects to see from the clutch, flags the fault and doesn't try to operate it again until next time you restart.

Clutch air gap should be between 16 and 31 thou and can be adjusted by undoing the centre nut, taking the outer part off, removing a shim or two from behind it and putting it back together.

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i have reset the air gap on the clutch, found the relay cut off pressure switches (behind the front bumper basically )so with the vehicle going there should be power to the switches . if there is power then the switch or switches are faulty, if no power check at hevac end for power.
can you remove switches without releasing the gas ? that's if there is any in there to release that is.
would the power be 12v or other, can i put power to the switch and see if it works or is that a no no.

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No, but you can unplug the pressure switch (the one with just two wires) and put a jumper to short the two wires together. If the compressor clutch engages then, it's either a bad connection at the switch, a bad switch or not enough refrigerant.

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You can change the trinary switch without releasing the gas. Theres a schrader valve inside. You can also do a continuity check across the switch. I had success by changing the trinary switch.

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I jumpered the pressure switch (two wire one) by getting an old switch, taking off the female plug, soldering jump wires to the back of it, filling it with silicone and then plugging it into the original male plug. (Putting it back to standard would take 30 seconds by swapping the plug onto the switch on the receiver/drier). Now whenever the AC comes on the condenser fans kick in as well, instead of the system waiting for very high pressure (therefore temp) in the system before engaging the fans. I did this as the coolant temp rise is quite noticeable with the AC running on 30+ degree days. This little bit helps fixing that issue as the fans run as soon as the compressor kicks in.

Mine usually sits around 88 degrees around town in warm weather, but with the AC on this would rise to say 92. With the fans running, it stays around 90, particularly in stop start traffic. On the road it makes no difference of course.

The trinary switch will still kick the fans into high gear if the system pressure rises too high, and eventually cut the AC out altogether if is rises above a set limit (and indeed won't let it activate if the pressure is too low).

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ok i had another go today , i replaced the universals in the rear shaft to find out its the front one is making the noise , will do that one another day. i bridged across the plug at the pressure switch and nothing happened so i checked for power no power so its an inside job , also checked for other faults and found one off coarse, O2 sensor rich, pulled the plugs and found a rusty ended lead, not touching the plug and ripped the end off another . also a couple of black plugs i also noticed the water level has gone down (no washed plugs) will keep an eye on that . back to the real issue.
i take it that their is a power issue inside the car , the nano says it has a grant for the AC to kick in so its not being stopped bye a fan or a relay so to speak or is there another reason for it to not work?

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If you are getting AC grant, then the HEVAC should be sending power out to engage the compressor, as long as the engine ECU agrees (GEMS - Engine - Others). Rather than trying to use a meter, as the power will only be applied for a short time before it decides that nothing is happening and stops the supply, you best bet is to use a light bulb. You should get power from pin 7 of C244 at the HEVAC (Black/Yellow wire) to the Trinary switch (and not the two pin one as I said earlier, oops), out of that on the White/Light Green wire to the compressor.

So I gave you duff info before and it is the plug at the Trinary switch that needs to be jumpered and not the pressure switch, sorry.