Looking for answers!!!

[outlaw_03]

So I have a 2013 silverado crew cab ltz.  Recently I have started having issues with my AC/heater.  (common denominator is the fan)  When I first start my truck, my AC runs fine.  However, after driving for 20 minutes or so, the air out of the vents gets weak and there is a noticeably louder noise under the passenger dash.  If I turn my AC off for a minute, it usually will work fine temporarily (5,10 minutes or so).   I already replaced the resistor thinking that would solve my problems.  I pulled the blower motor fan and it looked good.  While I had it out, I plugged the blower motor fan up to a battery and let it run for 20-25 minutes and it ran perfectly fine.

 

So can anyone enlighten me and what the problem may be?  Could the blower motor be bad even though it ran fine off the battery?

[swathdiver]

You can guess and throw parts at it or hook it up to a bi-directional scan tool like a Tech-2 or VXDIAG NANO with a Tablet and properly diagnose the problem.  Could be an actuator, could be low on freon, could be the controller, etc.

[davester]

You might also consider getting hi/lo pressure gauge setup for the a/c system, hook it up, record the pressures when it works and when it stops working (I would do it over a number of times), then research/talk to an a/c guy/read through the full service manual what the pressures should be.