1999 Explorer. AC compressor comes on and inside cools, but only down to
about 68 degrees or so via thermometer. Also, clutch on compressor does
not cycle on or off. Also, at various times, the compressor will just turn off and
not come back on, sometimes it does come back on. Most of the time the
clutch stays engaged. Any suggestions?
A high and low pressure reading would really help. I am also thinking you may have a blend door problem so the internal temp sensor is not getting a true reading of the A/C output.
I am thinking it is undercharged and possibly freezing up the evaporator, but I am not an A/C guy and not sure why I even answered the question. What do you thin Mr. Tennisshoes?
If that was the case then the air flow inside would be greatly reduced.
System is definetly undercharged temp at the vents should be around 40 degrees, the compressor keeps cycling because its probably getting a high pressure at the evaporator because theres no refridgerant. Seems likely that you have a leak or a restriction somewhere
Air coming out the vent is strong, no vent door problem. Air felt cold coming out, so I put the thermometer in the refrig, which I know is 36 degrees. Only got down to 60 on the dial, so obviously the dial is defective. Readings on gauges at 85 degrees ambient air temp are just under 30 lbs on low side and just under 200 lbs on high side. Add one can of dye 134A, once stablilzied, did not increase pressure readings much. Compressor still runs continuously.
accumulator gets cold, sweats and drips water.
Update. Knowing the thermometer was faulty, I removed the mercury thermometer from the patio and placed it in the direct air flow at center console. Got down to 38 degrees within a couple of minutes. Compressor still does not switch on and off, stays on.
Text book readings are 32 low side 150 high side, these will vary depending on outside temp. I would replace the low side clutch cycling switch and recheck.
Is the low side cycling switch the one which screws into the accumulator? If not, can you indicate an approximate location? Seeing as the vehicle is 17 years old, and no ac components changed as yet, may be time for some parts change.
Yes that's the one.
This is from the manufacturer service manual The A/C refrigerant system is a clutch cycling orifice tube type. The system components are: A/C compressor (19703). A/C clutch (2884). A/C condenser core (19712). A/C evaporator core (19860). suction accumulator/drier (19C836). connecting refrigerant lines. The refrigeration system operation is controlled by the: A/C evaporator core orifice (19D990). A/C cycling switch (19E561). A/C compressor pressure relief valve (19D644). A/C pressure cut-off switch (19D594). The refrigerant system incorporates an A/C compressor controlled by an A/C cycling switch. The A/C cycling switch senses A/C evaporator core pressure to control A/C compressor operation. An A/C compressor pressure relief valve is installed in the A/C manifold and tube (19D734) to protect the refrigerant system against excessively high refrigerant pressures. An A/C evaporator core orifice is installed in the condenser to evaporator tube (19835) to meter the liquid refrigerant into the A/C Based off the operation of the system on your vehicle. I would say its the A/C cycling switch. Heres the wiring diagram too
The switch is probably stuck open. Check for power at Black and Yellow wire at the A/C cycling switch
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