AC issue (Driver's side warmer)

[joemcc]

Hi everyone,

A few things to make sure I'm diagnosing this right...

AC line pressure is about 35#
Blows warm air Driver's side unless i stop moving or turn the fan down to low speed (then noticably cooler)
I can change from cold to hot, so actuator is doing something.

What steps would you take?

Joe

 

[Sparky]

If it is blowing cool air on the passenger side at all times then that should mean the AC system itself is OK as there is only one evap coil.

Is this the auto or manual climate control?

 

[joemcc]

Auto...

I have read people have replaced the actuators and ended up being low on refrigerant (doing the exact same thing) and others getting results with new actuators.

So I was wondering if there are some troubleshooting steps i can do.

Joe

 

[gmcman]

You can crawl under the drivers side dash and remove the temp actuator, then rotate the door by hand and see if you get cold air on the drivers side. I don't know off the top of my head which one is the temp but mine did the same thing and it turned out to be the actuator.

 

[Mooseman]

Actuator diagram located here:
http://gmtnation.com/forums/topic/2156-hvac-actuators-and-dash-removal/?p=161590

Depending on the model, some have a metal bracket right where the driver's temp actuator is located and is a bitch to remove. I've seen it in my Saab and an Envoy. Can't remember if there is a bracket in the TB.

 

[gmcman]

Actuator diagram located here:
http://gmtnation.com/forums/topic/2156-hvac-actuators-and-dash-removal/?p=161590

Depending on the model, some have a metal bracket right where the driver's temp actuator is located and is a bitch to remove. I've seen it in my Saab and an Envoy. Can't remember if there is a bracket in the TB.

Ha...yeah, now I remember....that's the one I removed. I think I took some pics but it took a long 1/4" extension and universal joint if I'm not mistaken.

 

[AbsoluteZero]

A low refrigerant charge can cause a side-to-side variation in discharge temperature. Refrigerant enters the evaporator, but if a low charge, will evaporate without cooling the entire surface of the evaporator. Not saying this is your problem but something to check.

 

[Escapepilot]

Mine has the same issue. It appears that the charge pressure is correct but the symptoms indicate it may be low (DIY kit so no accurate gauge). Cooler temps or lower speed = colder out of driver's side. Outside temps in mid 90s at highway speed = miserable drive. Had the instrument cluster out so loosened the manual A/C unit and radio and watched the actuators. They moved through 90 degrees, both sides, so I think they are ok.

 

[Rebuilt_SS]

Had a pen fall down one of my vents once, jamming the door partially open at all times. Bought a boroscope from Home Depot, found it, removed it, returned the boroscope.

I have a really hard time believing this could have anything to do with R134a charge as the output air is a shared chamber for all cold air (Driver/Passenger/Rear)

I say get a look at it. Removing the dash to do so is a huge nightmare and requires discharging the A/C, so a boroscope is the way to go.

-Tim

 

[Texan]

Escapepilot,
You really need to borrow or buy (Harbor Freight $55) a set of
gauges to analyze the AC system. What are the low and high
side pressures at 1500 rpm and ambient temperature?

 

[Tiggerr]

Escapepilot,
You really need to borrow or buy (Harbor Freight $55) a set of
gauges to analyze the AC system. What are the low and high
side pressures at 1500 rpm and ambient temperature?

I fail to see this logic. There's only one evap. If the evap gets cold, it's cooling. There's not an evap for the pass side and another for the driver. The problem has to lie in the blend doors/actuators, the vents ducts themselves, heater controls, or something.