Car Doctor Q&A: Why Is My Passenger Getting All the Cold Air?

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Summer’s here and so are air conditioning woes. Usually it’s a failure to cool at all, but this driver is complaining that all the cool air is aimed his passenger.

Q. I have a 2010 Honda Accord with 150,000 miles. The car runs great but the air conditioner is only cold on the passenger side. Eventually the cabin will get cool but there is warm air blowing out of the driver’s side vent.

I did some research online and found that this is typical of a air blending door, which look like a lot of work and pretty expensive. Is there someway to force the door closed so I can have cool air for the summer?

A. On your Honda Accord there are two motorized blend doors and it’s possible that the driver’s side is stuck partially open and allowing warm air into the cabin.

In the past I have used a flexible digital inspection scope in the air ducts to watch various doors open and close, but there’s a pretty good video here on YouTube that shows the same issue in a 2007 Honda Ridgeline. This problem was traced to a faulty servo motor that controls the blend door, which is a lot easier to fix than the blend door itself. It’s accessible from the interior, right near the accelerator pedal:

First things first, though, you want to make sure your AC system is working properly. You may find that there’s a leak in the system and it is low on refrigerant.

There are plenty of places that the air conditioner could be leaking but one common and very slow leak is where the air conditioner lines attach to the A/C expansion valve.

Apparently during assembly, strands of fabric keep the O-rings from sealing. If this is the case, the repair is pretty simple, evacuate and recover the refrigerant and replace the O-rings and recharge the system.

John Paul is senior manager of public affairs for AAA Northeast. A certified mechanic, Paul tests dozens of new cars each year and also hosts a radio show on AM 950