2013 Silverado 1500 AC issue

[Louis1799]

My ac compressor continues to run while the control unit is off as well as quits blowing air after about 25-30 movies on the highway. When I leave the ac "off" the expansion valve and the evaporator are  still frosting over.I have no issues with temperature and the system is fully charged. I'm stumped.

[Doug_Scott]

The compressor will run when the controls are set to defrost as well as when set to dash vents provided the external temp is above freezing. 

 

Don't understand what you mean by "quits blowing air". 

[Louis1799]

42 minutes ago, Doug_Scott said:

The compressor will run when the controls are set to defrost as well as when set to dash vents provided the external temp is above freezing. 

 

Don't understand what you mean by "quits blowing air". 

When I'm driving with the ac on, after about 25-30 minutes it quits gradually blowing air thru the vents. After I park the truck and give the evaporator and expansion valve ample time to defrost, the ac works normal again. That it is, until they freeze up again. 

[Doug_Scott]

6 hours ago, Louis1799 said:

When I'm driving with the ac on, after about 25-30 minutes it quits gradually blowing air thru the vents. After I park the truck and give the evaporator and expansion valve ample time to defrost, the ac works normal again. That it is, until they freeze up again. 

Forgot to ask if you have automatic or manual a/c.  You should only see frost forming on humid days and it should not impact the normal operation. 

 

When you say quits gradually are you referring to the fan speed or the temperature?  How long have you owned the truck? 

 

If you have automatic a/c, disconnect the ground cable first, then disconnect the positive cable. Touch the two disconnected cables together for a few seconds. Clean the connections on both cables and reconnect the positive cable first.  

[Louis1799]

I have the automatic ac and have only owned the truck for 2 months. The fan speed gradually decreases. I'll give your cable recommendation a shot. Thanks. 

[Doug_Scott]

Auto a/c works that way.  As the temp in the cabin approaches the temp set the fan will slow.  It should maintain that temperature automatically.  If you have the owners manual look at the section for the a/c and see if the manual is describing what you are seeing.  Removing battery connections is usually the first thing to do when dealing with auto a/c issues. 

[Louis1799]

19 hours ago, Doug_Scott said:

Auto a/c works that way.  As the temp in the cabin approaches the temp set the fan will slow.  It should maintain that temperature automatically.  If you have the owners manual look at the section for the a/c and see if the manual is describing what you are seeing.  Removing battery connections is usually the first thing to do when dealing with auto a/c issues. 

I'm aware of how auto ac works. Regardless if I run it on auto or manual, it quits blowing air after 25-30 minutes. The clutch is not disengaging whether the control unit is on or off. When I drive with the ac off, the accumulator and the evaporator are still frosting over due to the fact that the compressor is running because the clutch engages as soon as the ignition is turned on.