Mechanics

AIR CONDITIONER ALWAYS ON

1999 Kia Sportage

Air Conditioning problem
1999 Kia Sportage 4 cyl Four Wheel Drive Automatic 127000 miles

The air conditioner compressor is always cycling on and off even when all controls on the dash are put to OFF. It doesnt matter if the AC switch is pressed or if the AC light is on or off. It doesn't matter where any control is, the AC is on. Everything else in the air system works ok.
That includes the condensor fan.

I had to pull the fuse in order to shut down the AC. This also turned off the condensor fan even though it has it's own fuse which was NOT removed.

Please help
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Wpharben1
April 9, 2009.



A/C Compressor Control Circuit
When ignition is turned on, battery voltage is applied to A/C relay and A/C cut relay. The A/C cut relay and A/C relay are located behind glove box, in passenger compartment. When A/C switch and blower motor switch are turned on, ground is supplied to A/C relay which energizes A/C relay. When A/C relay is energized, battery voltage is supplied to A/C condenser fan motor through ADD fuse (30-amp), located in engine compartment fuse/relay box.
When A/C relay is energized, a ground is supplied to the Engine Control Module (ECM) A/C request input and A/C clutch control signals. The ECM A/C clutch control ground passes through the A/C thermostat and dual pressure switches. If both switches are closed, the ECM will energize A/C cut relay and supply battery voltage to compressor clutch. Battery voltage used to energize A/C clutch is supplied to A/C cut relay through REAR WIPER fuse (10-amp), located in passenger compartment fuse box.

Dave H
Apr 10, 2009.