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MDX AC blowing warm air on driver's side, cold on passenger

0

Mark S. · rep 0 · May 25, 3:44 AM · 1 replies · solved · Question

Vehicle: 2018 Acura MDX Technology

I'm having a weird issue with the AC in my 2018 Acura MDX Technology. The passenger side blows nice and cold, but the driver's side, including the rear driver's side vent, is blowing noticeably warmer air. It's like the dual-zone climate control isn't working correctly.

I've tried adjusting the temperature settings individually for both sides, but it doesn't seem to make a difference for the driver's side. This just started happening a few weeks ago, and it's getting hot here in Texas!

Has anyone experienced this specific problem with their 2016-2020 MDX? What was the cause, and how difficult was the fix? Thanks for any insights!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 3:44 AM

0

The issue you're describing, where one side of the vehicle's climate control blows warm air while the other blows cold, is a classic symptom of a problem within the dual-zone climate control system. This is a common complaint across many modern vehicles, including the Acura MDX.

Causes and Potential Solutions:

  1. Blend Door Actuator Failure: The most common cause is a faulty blend door actuator. These small electric motors control 'doors' inside the HVAC system, directing air over the heater core or evaporator coil. If the driver's side actuator is stuck or malfunctioning, it might not be directing air over the cold evaporator coil, or it could be stuck directing it over the heater core.
  2. Low Refrigerant (Unlikely for One Side): While low refrigerant can cause poor cooling, it typically affects all vents, not just one side. If it were low, you'd likely experience reduced cooling across the board. However, it's always good to rule out.
  3. Clogged Expansion Valve or Orifice Tube: A partial clog could theoretically restrict refrigerant flow to one side of the evaporator, but this is less common than an actuator issue.
  4. HVAC Control Unit Glitch: Less likely, but a software glitch or internal fault in the main HVAC control unit could send incorrect signals to the actuators.

When to See a Shop:

  • As soon as possible, especially with the Texas heat. While it's not a safety issue, comfort is important.
  • A professional technician can perform diagnostics to determine if an actuator is faulty. This often involves listening for actuator movement, checking for diagnostic trouble codes (though blend door issues don't always trigger OBD-II codes), and physically inspecting the components.
  • Replacing a blend door actuator can range from relatively simple to very involved, depending on its location within the dashboard. Some require significant dashboard disassembly, making it a job best left to experienced mechanics.
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