A/C inop
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A/C inop
My 07 Expedition will not engage the ac compressor clutch. No voltage at the plug. ALL relays tested good and fuses also tested good. I know there has to be either a compressor cycling switch or low pressure switch on the low pressure side line somewhere BUT it's NOT on or near the accumulator, evaporator or the front ac low pressure hose. Everyone tells me it's by the fire wall on the right(passenger) side which would be near the evaporator core. Is it on the rear system pipes/hoses?
Hotshot
Joined: Jan 2004
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From: St Louis
This ain't your daddy's AC system anymore, it's all computer-controlled.
Nope. There is a pressure transducer that measures pressure in the sealed system and reports that pressure to the PCM. The PCM, based on programming and the inputs from the climate control module, either activates the clutch relay or doesn't. You CANNOT simply jump the transducer as you could with the old cycling switches.
First thing to do is check if you have minimum static pressure (> 42 psi) in the system with a gauge (checking for discharged system). If you do have the minimum pressure, you're going to need a scan tool to read the PCM and climate controls PIDs in order to accurately diagnose.
I know there has to be either a compressor cycling switch or low pressure switch on the low pressure side line somewhere
First thing to do is check if you have minimum static pressure (> 42 psi) in the system with a gauge (checking for discharged system). If you do have the minimum pressure, you're going to need a scan tool to read the PCM and climate controls PIDs in order to accurately diagnose.
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BigSix1
1987 - 1996 F150 & Larger F-Series Trucks
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Jun 1, 2011 08:22 PM
