AC takes forever to turn on, works great when it does


Maxinstl

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My AC compressor takes 10-15 minutes to kick on after my car has started. It works great once it kicks, but I don't know why it takes so long. The 2 pressure switches look fine, I've checked the low side pressure when running, it's 35 psi, it isn't crying when running, and its ice cold when its on. This is a consistent issue. Does this sound like a bad pressure switch? I've checked the low side pressure after the truck has been sitting a while off and it's about 135 psi, and when it (eventually) kicks on it drops to 35 psi. From my understanding that's normal. I don't want to change switches if that's not the issue, since you can't return them once you put them on...

Thanks!
 


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pjtoledo

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cold engine lockout???? if equipped with one it's a sensor in a heater hose. my Taurus' have one, not sure if Rangers do.
 

telsar

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It might be that the clutch gap is a little too far and by hitting a bump in the road it catches and engages. Regardless, check the power on the clutch is on and shove the clutch in with a big screw driver if it is.

There are shim washers under the clutch.

This is just a guess, but it happens.
 

RonD

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Tap on AC clutch after turning it on, could be an "air gap" issue, AC clutch is an electro-magnet, when powered up its suppose to pull in the clutch and engage the compressor, if there is too big of a "gap" there is not enough magnetic force to pull it in, engine vibration or a bump in the road may get it to engage.

2002 Ranger AC uses the PCM(engine computer)
The pressure switches are GROUNDS, in series, that connect to the PCM(pin 86)
When you turn AC on that signal goes to the PCM(pin 41)
The PCM then connects the pressure switch Ground(pin 86) to the AC Clutch Relay's Ground(pin 69)
(So if a pressure switch is OPEN then no ground for AC relay)

This closes the AC Clutch relay and sends 12volts to the AC Clutch coil, activates the magnet

You could try swapping AC Clutch relay(in engine fuse box) with another relay in the engine fuse box

PCM will disconnect AC relay Ground IF, throttle is at WOT(wide open) giving max power to driver
It will also disconnect the ground if ECT sensor(engine temp) gets too high, to prevent over heating
 
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