Air Conditioning Trouble shooting

[j98]

Have a 2011 GMC Sierra Denali, cannot get the A/C to work.

 

1. Tried to do a recharge with a bottle from Autozone. Gauge went into the red, signifying there was other issues.

2. Discovered when I turned on the AC, the clutch would not engage. Can spin clutch freely by hand when truck is off.

3. Both the fuse and the relay tested good, swapped them out with new ones just to be sure. No change. 

 

Can someone point me in the right direction as to what I should be looking into next? 

[carnau]

2 hours ago, j98 said:

Have a 2011 GMC Sierra Denali, cannot get the A/C to work.

 

1. Tried to do a recharge with a bottle from Autozone. Gauge went into the red, signifying there was other issues.

2. Discovered when I turned on the AC, the clutch would not engage. Can spin clutch freely by hand when truck is off.

3. Both the fuse and the relay tested good, swapped them out with new ones just to be sure. No change. 

 

Can someone point me in the right direction as to what I should be looking into next? 

Ok, so there is a lot we need to unpack here. 

 

You can test the ac compressor and the wiring to the AC compressor by removing the AC compressor relay and jumpering terminals 87 to 30. This will power the compressor on and let you know if the wiring is good and if the clutch is able to engage. DO NOT LEAVE THE WIRE IN THERE THINKING IT WILL RUN THE AC FOR THE VEHICLE!!

 

If you jumper 87 to 30 and it engages. You need to find out what is prohibiting it. In order to do this you need a Gauge kit or a inexpensive scan tool that will give you AC request information. It will tell you what is keeping your system from enabling. (high pressure, Low pressure, ect)  ( Blue driver is probably the least expensive that will give you Body data. https://amzn.to/36WXKBz )

 

From there we can move forward.

 

 

[j98]

@carnau 

 

Thank you for this info, I will give it a shot. Will a regular scanner typically not read body data? 

[rjgti]

no

[sefiroxx]

Your system has Freon. The cheap fill guage should be used / read with the compressor engaged.

You might have:
, broken low or hi pressure switch
. Bad relay
. Bad temp sensor
. Bad control system.

If you are going to bypass the relay, be sure you have a full set of changes on the system. If you over pressurized the system, you can blow the compressor.

[j98]

On 6/2/2020 at 4:08 PM, carnau said:

Ok, so there is a lot we need to unpack here. 

 

You can test the ac compressor and the wiring to the AC compressor by removing the AC compressor relay and jumpering terminals 87 to 30. This will power the compressor on and let you know if the wiring is good and if the clutch is able to engage. DO NOT LEAVE THE WIRE IN THERE THINKING IT WILL RUN THE AC FOR THE VEHICLE!!

 

If you jumper 87 to 30 and it engages. You need to find out what is prohibiting it. In order to do this you need a Gauge kit or a inexpensive scan tool that will give you AC request information. It will tell you what is keeping your system from enabling. (high pressure, Low pressure, ect)  ( Blue driver is probably the least expensive that will give you Body data. https://amzn.to/36WXKBz )

 

From there we can move forward.

 

 

Soon as I jumped the relay I heard the clutch engage. A/C worked. Waiting for scanner to show up to read the body codes.

 

Thanks for the help!