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Discussion Starter · #1 ·
I know this is the second time i have posted this question , but hoping that the new subject title will draw someones attention that has an idea or fix. I m afraid im gonna cause damage to my clutch on compressor from constant off and on. My 95 pick up has a relay on the passenger side behind the kick plate under the glove box at idle it cycles on and off every 5 seconds which causes the trucks idle to rise and fall, but doesnt seem to do it while running down the road. It might still be doing it though because obviously while running down the road you cant hear the difference like when at idle. thanks in advance for any advice or recommendations.
 

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is the cycling all the time or just when you have the ac on if its just when the ac is on get the r134a or r12 level checks that is a sign its low
 

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Discussion Starter · #3 ·
i put a gauge and refill 134a to add more because i thought the same thing but it was in the green so im wandering if i may have some restriction in the evaporator or somewhere in the system would that cause a false low pressure reading but not be low of 134a?
 

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Check the evaporator temperature sensor. The relay clicks when the evaporator temperature sensor turns the compressor on and off to keep the evaporator cold but not frozen.
 

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Does yours have a condenser fan? (electric fan between the grill and condenser). If it does, make sure its working. If it doesnt you might think about adding one. For whatever reason Isuzu didnt put the fans on 2nd gen rodeos with 5 speeds but automatics have them. My a/c would shut off when stopped most time and not run again until I started moving. I stripped out all the wiring and plugs in the fuse box from an automatic and added one to mine. Now it actually works right. I dont know what other vehicles they did this on but I know some troopers dont have the fans either.
 

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It is either switching because the high side is hitting the high limit or the low side is hitting the low limit or the core is freezing.

My guess is, since you are sitting still, that the high side is hitting the upper limit. If your sure the charge is right then adding a fan to the condenser will be the best solution.
 

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Discussion Starter · #7 ·
I appreciate the info I spoke with a heating and air guy today at my little girls birthday party and he said the same thing sounds like to him it was a high pressure in the condenser issue said first he would check to make sure there was no trash built up between the radiator and condenser, which I doubt their is but I will check. Second he said maybe flushing the radiator and adding fresh winter/summer coolant may help, this is something I have been needing to do anyway, but the fan makes the most sense to me now that its brought to my attention, theory has it that enough air is not being brought through the condenser sitting still, but going down the road of course air is being forced through it. Excellent advice and much appreciated will check into the fan this week, wander what the cost would be and how I would go about mounting it and where I would tie the wiring in so that it cycles on when I am sitting still ?
 
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