2011 gmc acadia. A/C blows hot, somtimes cold. Hisses and can hear clutch. Had it checked for leaks with dye and none found. Replaced actuator about 6 mos ago. Please advisd. Condensor? Thoughts?

Blend Door Actuator issue which is a servo operated door that closes off the heat and direct the cold air instead. It is a known issue on them. See the videos.

https://www.google.com/search?q=2011+gmc+acadia+blowing+hot+air+on+driver+side

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your on the right track! your blend door is broken or your blend door actuator is broken.

You might have a bad actuator ?

Not the fuse. Replace the driver side control motor. Under the dash at the center console.

Temperature blend door actuator . There are electric motors behind the instrument panel that control air flow direction. GM calls it a Temperature Valve Actuator Replacement - Left Side
Instrument Panel Insulator Panel Replacement - Left Side (Acadia)

Callout

Component Name
1
Push-pin Fasteners (Qty: 3)
2
Insulator/Closeout Panel - Left
Procedure Disconnect the electrical connectors.
Caution: In order to avoid actuator damage, DO NOT apply power to the actuator when it is not installed in the HVAC module.
Preliminary Procedure Remove the instrument panel insulator - left side. Refer to Instrument Panel Insulator Panel Replacement - Left Side.
1
Left Temperature Actuator Screw (Qty: 3)
Caution: Refer to Fastener Caution in the Preface section.
Tighten
2 N?·m (18 lb in)
2
Left Temperature Actuator
Procedure

1. Disconnect the electrical connectors.
2. Re-calibrate the right temperature actuator. Refer to Actuator Recalibration.

Either bad switch or actuators door

check the actuator door on the heater that directs the air. It will be in the middle of the dash under the dash.

several reasons why ac not blowing cold. Most common a freon leak causing system to be undercharged. electrical and component failure may also be a factor. You need a set of gauges. find the compressor start engine with a c off the compressor clutch wont be engaged now turn it in on and see if clutch engages. If it engages you need to know what your low and high side readings are. You should have your system diagnosed be a seasoned pro...... If clutch does not engage you probably are low on freon. Put dye in the system so you know where the leak is when it leaks again. you can buy freon with dye already in it.

Not sure if I'm too late to answer this one, but you're describing a low refrigerant condition. The hissing noise and constant cycling of the compressor clutch are indicators of that. You should recover the system, record how much refrigerant was recovered, evacuate the system (with a vacuum pump), add A/C dye, and recharge the system to capacity. Common leak areas on these vehicles include the A/C condenser (located in front of the radiator), and the evaporator (located inside the dash, and requires complete removal of the interior dash to replace it). If you can't find a visible leak after running the recharged system with dye for several weeks and it starts to blow warm again, you will need to use an R-134a leak detector to "sniff" areas of the system for a refrigerant leak.

Actuator for the venting system not functioning properly.