I posted this on a different thread but I always run a diagnostic test with the A/C before I try to rip things apart just to see if there was a code that would direct me to the problem. Hope it helps
I would run a Diagnostic Trouble Code (DTC) test with the A/C system and see what codes, if any, come up and then go from there. The test is run right from the dash panel without any needed equipment. I will give you the steps how to do this but you will need to post the code that comes up because there are too many codes to list on here.
1. Turn the ignition to the On position.
2. Turn the blower motor control to the ON position.
3. Press the A/C mode switch (A/C button with the snow flake) down, turn the blower motor control to the OFF position, wait until both LEDs illuminate (approximately 5 seconds) and then release the A/C switch. If there are active or stored DTCs to display, the A/C status indicator (Yellow light on the snow flake button) will begin to flash. If there are no active or stored DTCs to display, the LEDs on the A/C-heater control will turn off and the system will automatically exit the mode of operation.
4. To manually exit Display DTC Mode, either turn the ignition off or disconnect the negative battery cable from the battery
Here is how you will read the code that is displayed.
Active and stored DTCs for the MTC system have an assigned code number. The A/C status indicator flashes in a series of pulses to display the code numbers. Each pulse has an indicator on time of 0.5 seconds. The tens unit value is flashed first followed by the ones unit value. A 2.0 second indicator off-time separates the unit values. When displaying multiple DTCs, the A/C status indicator will go off for five seconds before displaying the next DTC. After displaying all DTC's, the sequence will repeat until exiting Display DTC Mode. Just push the A/C button to exit the diagnostic mode.
Sorry if I made it to elementary (yellow light, snow flake...) I just wanted to make sure we were on the same page.