Air Conditioner Not Working Right

[Chuck Bunyon]

I'm having a periodic ac issue. Everything will work fine when it is cool outside but the ac sometimee gets warm when it is warm outside and i cant get it to cool down. The compressor works and the canister and all the lines stay cold but the cold air doesn't reach the interior. I read somewhere about the ambient air temp sensor but I'm not thinking that's right. Any ideas?

 

[freddyboy61]

The ambient air temperature can be a problem if you have the digital display HVAC system. The system relies on the sensor to set cooling and heating. If you have the digital system, what does the exterior temperature display read?

If you have the manual system(with sliders), you may have a problem with the temperature blend actuator, but it would only affect one side. This could happen on the digital system as well.

Please fill out your profile so we know your vehicle setup.

 

[Mooseman]

Have you tested the fan clutch?
http://gmtnation.com/forums/topic/12497-how-to-test-the-electro-viscous-fan-clutch/

 

[Chuck Bunyon]

The clutch works fine. I can see and heard it engage. The condenser and all the metal lines get cold. The cold just doesn't reach the interior.

 

[Mooseman]

The fan clutch or compressor clutch?

When it's warm and the system isn't blowing cold, check to see if the compressor clutch slips. As the pressure gets higher, it's harder for the compressor and the clutch may slip. I had that before I removed a shim from the compressor clutch, reducing the gap.

With the A/C on, turn up the temperature to full hot and notice if the blend door(s) move and it gets hot. Then turn it to cold and see if it changes. Maybe try doing a reset by pulling the HVAC-B fuse for a minute, putting it back in then turning the key to RUN but don't start the engine. Let it do its thing for a couple of minutes and try it out to see if it does it again.

 

[Chuck Bunyon]

Both the fan and compressor clutches engage. The blend door is already on the cold side since it blows cold then quite and blow ambient air.

 

[Chuck Bunyon]

I will try to pull the fuse the next time it does it.

 

[Chuck Bunyon]

There is a sensor at the top of the canister. I unplugged it then plugged it back in and it worked for a while. What sensor is that?

 

[Texan]

That sensor is the low pressure sensor.
Did you check the connection for corrosion?
Use contact cleaner (Radio Shack).