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Discussion Starter #1
Hi Guys. Im having a problem with the AC in my car. It has stopped working and I have done some investigation to try and find out what is going on. I plugged in my Opcom and got these readings from the ECU:

A/C Pressure: 580kpa
A/C Information Switch: Inactive
A/C Relay: Inactive
A/C Cutoff Mode: System OK

When i press the A/C switch, the light comes on but the relay doesnt engage. When i do an A/C relay test through opcom, you can hear the relay click and the opcom change to Active. However when I try it when the car is running, the relay wont click and shows as Inactive

Any ideas?
 

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That pressure looks to be on the low side.
Too low and the system won't engage.
 

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Discussion Starter #4
Done a bit more digging today. The pressure has risen to about 660 - 680kpa and still showing as system ok. When I press the A/C button, the light comes on but the A/C Information remains as inactive. Am I right to suspect that my heater control panel is at fault?
 

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Done a bit more digging today. The pressure has risen to about 660 - 680kpa and still showing as system ok. When I press the A/C button, the light comes on but the A/C Information remains as inactive. Am I right to suspect that my heater control panel is at fault?
Sorry to butt in, on my first zafira, I had the same as this, in the end it was the pump being knackered


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If it is too high as previous comment suggested that would make sense as this happened to me took it to garage and he said it was way to high and the previous owner probably bought one of them do it yourself aircon refill tins and put to much in he drained and put the correct amount in
 

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Discussion Starter #12
I got it done at Kwik Fit last year properly. I used a tin on a previous car many moons ago but never again. I will take it in and see if they can work their magic on it
 

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UPDATE - Just had a bit of jiggery pokery in the UEC and managed to get the air con running. On the air con relay, I measured these pins to earth (85 = 4.3v, 86 = 14v, 30 = 14v). I shorted pins 30 to 85 as if the relay was working and the air con kicked in and started blowing cold air so I know that the clutch and compressor works. Im putting my money on a fault with the heater control panel. Its the one with the manual air con button. On opcom, it still shows as System OK. When I press the AC button, the AC Information switch does not change. Im thinking that the unit is faulty and wont send a signal to the ECU telling it to trigger the relay. I know the relay works as the output test will cause it to click
 

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Discussion Starter #15
Thanks Allyj82 :) I have checked behind the fan controls and nothing appears to be visibly wrong. I've ordered a new heater control panel off ebay so will try that and see if that solves the problem. It wouldn't surprise me if something has gone electrically wrong with the control panel. This car certainly keeps me on my toes!!
 

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Discussion Starter #17
My new heater control panel arrived, fitted it in, but still no luck with the A/C coming on :( Starting to think that it could now be down to the ECU. I have already got problems with it when it comes to cold starting. Maybe its not earthing the relay anymore for the A/C. I've been putting off the new ECU for a while. I have been in OPCOM and checked that the AC is programmed in the CANBUS settings (with clutch) but still no luck. Damn Zafiras!
 

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Not a good news mate.
Change the relay, I know you tested it and it all worked but relays do like to be a bit temperamental.
I don't know much about ECUs but i think if you press the AC button the opcom should reflect that in measuring blocks, so if it does I think your ECU is good

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Discussion Starter #19
I swapped the relay for another one and no luck sadly. I pressed the AC button whilst in OPCOM and kept an eye on the ac information switch but that remained as Inactive. Its something between that button and the ECU thats not communicating. Bring back the old days of no ECU. Just wires and an engine ;)
 

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I swapped the relay for another one and no luck sadly. I pressed the AC button whilst in OPCOM and kept an eye on the ac information switch but that remained as Inactive. Its something between that button and the ECU thats not communicating. Bring back the old days of no ECU. Just wires and an engine ;)
Seems this happens from time to time on Astra H & no one finds a cure.
 
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