AC problems.....

[darth foop]

so my AC has quit working on me....... Resistance @ compressor plug was 12.2 ohms (within spec). R134a good now, no codes present, fan turns on with ac button, voltage coming from harness is 9v on the one wire when ac is suppose to be on, fed compressor direct 12v to the one pin that was showing 9v and compressor didn't engage. Don't know if terminal has to be plugged in then supply it with 12v to see if compressor kicks on or not.

is the compressor shot? or am I missing something here!?

[diagnosticator]

The compressor is a variable displacement type unit. It does not have a drive clutch. The compressor is controlled from the HVAC controller in the dash, and the controller sends a PWM control signal to the compressor to vary pumping displacement. The PWM control voltage is why you measured 9 volts on the control signal wire. The average voltage measured, 9 volts, represents the duty cycle (9/12=.75, or 75 percent duty cycle) of the PWM control voltage to the compressor.

[darth foop]

The compressor is a variable displacement type unit. It does not have a drive clutch. The compressor is controlled from the HVAC controller in the dash, and the controller sends a PWM control signal to the compressor to vary pumping displacement. The PWM control voltage is why you measured 9 volts on the control signal wire. The average voltage measured, 9 volts, represents the duty cycle (9/12=.75, or 75 percent duty cycle) of the PWM control voltage to the compressor.

gotcha. So if the compressor is getting the correct voltage but I'm still not getting cold air, is it safe to assume the compressor is bad? The whole AC system is confusing to me!