03 Expy AC wont cycle off; killing my efans
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Member
Joined: Dec 2011
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From: Southern NJ
03 Expy AC wont cycle off; killing my efans
Hoping somebody could help. the Ex has 133K miles. I've replaced the hi pressure sensor and the expansion valve ***'y (has the low pressure and thermostat sensors). The AC kicks on with MAX or the normal selector + the AC button. However it will not cycle off. My efans are connected via the switch which looks at AC compressor voltage and turns the fans on/off with the compressor.
My engine overheated on the way home, and found the efan fuse melted. when i replaced it, the fans came back on with the AC, and then I realized they no longer turn off becaue the compressor doesn't turn off.
this happens regardless of ambient air temp.
I have check the relay, and it is functioning correctly. Hi pressure was around 200, low was around 30-40. Air temp was about 80 degrees. And I have the dual/ rear AC unit as well.
I am wondering if my pressure is just not high enough for the dual system, or, maybe the evap core is dirty, not getting enough air flow, and thus not cycling the thermo switch?
At my whit's end. any help or advice is greatly appreciated.
Thanks.
My engine overheated on the way home, and found the efan fuse melted. when i replaced it, the fans came back on with the AC, and then I realized they no longer turn off becaue the compressor doesn't turn off.
this happens regardless of ambient air temp.
I have check the relay, and it is functioning correctly. Hi pressure was around 200, low was around 30-40. Air temp was about 80 degrees. And I have the dual/ rear AC unit as well.
I am wondering if my pressure is just not high enough for the dual system, or, maybe the evap core is dirty, not getting enough air flow, and thus not cycling the thermo switch?
At my whit's end. any help or advice is greatly appreciated.
Thanks.
Senior Member
Joined: Oct 2002
Posts: 7,295
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From: St. Louis (Out in the woods)
The compressor is supposed to run as long as the control switches tell it to be turned on and while the low side pressure is within the thermostatic switch's range. They usually switch off around 22 psi descending and switch back on around 45 psi. The low pressure may vary based on the cabin's cooling load.
It is perfectly normal for the compressor to operate at 100% duty cycle during the summer.
It sounds like the efan wiring isn't able to supply the current needed to operate them, probably due to cheap or improperly specified construction or materials. The efans should be capable of also operating at 100% duty cycle. Contact their manufacturer.
It is perfectly normal for the compressor to operate at 100% duty cycle during the summer.
It sounds like the efan wiring isn't able to supply the current needed to operate them, probably due to cheap or improperly specified construction or materials. The efans should be capable of also operating at 100% duty cycle. Contact their manufacturer.
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Joined: Dec 2011
Posts: 12
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From: Southern NJ
Hmmm?
well, I've had the fans in there for about 3 years now. this is the first time i've ever seen the comp just run and run and run. evan at idle, on days when it is not terribly hot.
All the components of the fan system are good. the fan is by FAL. 10 ga wire throughout. the controller is mounted inside the cab, up under and behind the glove box. stays cool, dry and dust free.
I agree the fuse blowing is suspicious. but so is the constantly running AC comp. never done that before that i can remember.
All the components of the fan system are good. the fan is by FAL. 10 ga wire throughout. the controller is mounted inside the cab, up under and behind the glove box. stays cool, dry and dust free.
I agree the fuse blowing is suspicious. but so is the constantly running AC comp. never done that before that i can remember.