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Bighorn Air conditioning problem...

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Bighorn Air conditioning problem...

Postby tonywbb » Fri Nov 17, 2017 1:03 pm

2002 isuzu trooper / bighorn / monterey

A/C works perfectly and is nice and cold from cold engine start and will stay working all day long, as long as the vehicle is not turned off.
It will intermittently start working sometimes after hot start but only rarely.
I have done some basic diagnostics:
When it is working the a/c clutch is working correctly and there is a bright 12v from my test light to the a/c pump wire.
When it is not the clutch is not working properly eg the pump is not spinning, when I put a test light on the wire there is only a very faint glow.
As soon as I leave it to cool down the a/c works fine again.

Any ideas would be much appreciated. -thanks.
tonywbb
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Country: New Zealand
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Vehicle: 2002 bighorn (monteray)

Re: Bighorn Air conditioning problem...

Postby geeves » Fri Nov 17, 2017 1:29 pm

Bad connection or bad relay. What happens if you make a fused test lead and connect direct from the battery to the air con? Use a 10 amp fuse
Sanding your knuckles before starting work can help. That way you cant skin them
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geeves
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Re: Bighorn Air conditioning problem...

Postby tonywbb » Fri Nov 17, 2017 2:46 pm

will try that tomorrow and post results.
tonywbb
Isuzu Baby
 
Posts: 4
Joined: Fri Nov 17, 2017 12:34 pm
Age: 35
Country: New Zealand
City: Auckland
Vehicle: 2002 bighorn (monteray)

Re: Bighorn Air conditioning problem...

Postby tonywbb » Mon Dec 18, 2017 5:57 am

sorry for the delay hasn't been that hot until now. I have tried the fused link from battery to the compressor and it works perfectly as in the clutch engages and disengages instantly, also found the relay that is labeled "A/C(thermo)" and swapped with one which I know is good but that made no difference.
Last edited by tonywbb on Mon Dec 18, 2017 6:20 am, edited 1 time in total.
tonywbb
Isuzu Baby
 
Posts: 4
Joined: Fri Nov 17, 2017 12:34 pm
Age: 35
Country: New Zealand
City: Auckland
Vehicle: 2002 bighorn (monteray)

Re: Bighorn Air conditioning problem...

Postby tonywbb » Mon Dec 18, 2017 6:15 am

Another observation I have made is with the ignition on and the engine NOT running there is a very faint glow on my test light when connected to the compressor clutch wire. Even when I remove the relay that is labeled "A/C(thermo)" the glow is still there. Is this normal?
Is there another relay somewhere for the compressor pump clutch? I cannot see anything relating to this in the fuse box in the engine bay.
Is there a pressure switch somewhere? if so where?
I also have pressure gauge that I can connect to the low side for further diagnostics.
Any and all help very much appreciated!
tonywbb
Isuzu Baby
 
Posts: 4
Joined: Fri Nov 17, 2017 12:34 pm
Age: 35
Country: New Zealand
City: Auckland
Vehicle: 2002 bighorn (monteray)


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