A/C air flow drops off

[SRehberg]

We recently bought a 2003 2500 4x4 with approx. 85K. After using the A/C for an hour or so the air flow from the ducts drops off dramatically. The blower sounds like it's blowing against something. If you shut the A/C off for a minute everything resumes to normal. Is this unique to the 3rd gen or just a bug in this particular truck? Any thoughts are appreciated.

 

[Bill Stockard]

The refrigerant charge may be low causing the evaporator to freeze up. It usually takes longer than a minute for it to thaw and resume normal air flow, however. My truck did similarly when it was new. The Dodge dealer A/C tech attached a set of gauges and determined the charge was low. He added a few ounces of refrigerant to the system and it never has done it again.



Bill

 

[ASchwartz]

The refrigerant charge may be low causing the evaporator to freeze up. It usually takes longer than a minute for it to thaw and resume normal air flow, however. My truck did similarly when it was new. The Dodge dealer A/C tech attached a set of gauges and determined the charge was low. He added a few ounces of refrigerant to the system and it never has done it again.



Bill

Ditto. By the way in the meantime, if you change the thermostat to hot, you will defrost sooner.

 

[SRehberg]

Thanks for the replies. I had considered the evaporator freezing but reasoned it would take longer to thaw that block of ice. Perhaps it isn't freezing that much and quickly thaws so we'll slap the gauges on it and see what it shows; it sure beats tearing things apart

 

[BMeier]

there is a problem with the vent door in the HVAC box. The door strips out at the motor and the flap drops down blocking air flow. You probably have this going on with yours. I had just replaced the door on mine, a buddies, and a guy I work with, all 03's.

 

[ASchwartz]

there is a problem with the vent door in the HVAC box. The door strips out at the motor and the flap drops down blocking air flow. You probably have this going on with yours. I had just replaced the door on mine, a buddies, and a guy I work with, all 03's.

Labor on replacing the door is much for costly then charging the system. I'd suggest starting there, since you do have a normal amount of flow and then none and once you let the system sit for a bit it is game on.