A/C blowing lukewarm air?

2012 DODGE RAM
176,000 MILES • 5.7L • V8 • 4WD • AUTOMATIC
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LEO120
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Driver side vents are blowing lukewarm air. The passenger side is nice and cold. heat works on all modes. A/C is charged and repaired all leaks.
Which blend door actuator, or the door itself should i check or replace?
Jul 21, 2025 at 1:34 PM
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STRAILER
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Yep, this happens when the driver side blend door actuator goes out, here is the location and how to replace it. Check out the images (below). Let us know if you need anything else.

Jul 21, 2025 at 5:59 PM
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KRAKENAUTO
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Since your driver’s side is lukewarm but the passenger’s side blows cold, while heat works normally and refrigerant charge is good, the issue almost always comes down to the driver side temperature blend door or its actuator (most common).

What to check:

1. Driver Side Blend Door Actuator (Left Temp Door Actuator)

Location: Usually mounted on the driver side of the HVAC box, under the dash near the steering column.

Signs of failure: clicking noises, not responding to temp knob, or stuck in one position.

2. Blend Door Itself
The plastic doors on these Rams are known to crack at the pivot or break entirely. Even if you replace the actuator, the door may not move if it’s broken.

If the actuator turns but the air doesn’t change, the door is likely broken.

3. Calibration
Sometimes the actuators just lose calibration. You can try pulling the HVAC fuse (or disconnect battery for ~10 minutes) and letting the system recalibrate when restarted. Worth a shot before tearing into it.

Hope this helps.
Sep 27, 2025 at 12:56 PM
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