Hi all. This is another driver’s side hot, passenger side cold problem, with a few differences that might be relevant. According to the posts below, the causes could be low refrigerant pressure requiring recharging of the AC system or a faulty evaporator. I have an 07 Accord EX-L. This morning it suddenly starting dumping *hot* air (not ambient temperature) on the driver side while the passenger side blew ice cold (I checked to make sure dual zone wasn’t turned on). Some factors which might set my case apart:

1. The problem went away after about an hour of highway driving. Does that narrow anything down? Could the problem come and go like this with an underpressured AC system? What's surprising to me is that the problem came out of nowhere.

2. The climate control system’s temperature setting has always been wonky (I bought the car used four years ago). For a comfortable temperature in the summer the temp needs to be set to about 26C degrees (79F), but the air coming out the vents is much cooler. I replaced the cabin temperature sensor right after buying the car but that didn’t make a difference. I've half-convinced myself this particular problem is caused by some super expensive electronic circuit board that requires taking the entire dash apart.

3. There are no HVAC codes flashing (see below on how to check codes).

4. No problems with blowing heat on either side with engine running.

This problem just happened so I haven’t had time to check anything else myself. Just wondering whether anything I’ve noted might narrow things down before I go any further.

Thanks in advance,
ND


For anyone with the same problem after me, here’s a list of previous posts on the same problem:

https://www.hondaaccordforum.com/for...er-side-47530/

https://www.hondaaccordforum.com/for...old-air-47615/

https://www.hondaaccordforum.com/for...houghts-25886/

https://www.hondaaccordforum.com/for...-driver-46627/

https://www.hondaaccordforum.com/for...cord-ex-32636/

How to Check HVAC codes: https://www.hondaaccordforum.com/for...94/#post370304

 

It is a high probability it is due to low refrigerant since there are no trouble code present. Also, see this other thread:

https://www.hondaaccordforum.com/for...e-vents-62777/

 

I finally got around to dropping the car off at a mechanic (not Honda). The AC was normal for 2+ weeks but started acting up a few days ago. Mechanic claims that the refrigerant level is fine, and that he has diagnostic equipment that will ID the problem. I offered to send him the link posted above but he wasn't interested. Does anyone happen to know, will generic AC diagnostic tools (not Honda specific) be able to ID the problem?
thx.

 

Further update: The mechanic was unable to find any problem with the system - by the time I dropped the car off, the AC was working again. Does anyone have any thoughts on how to proceed given the problem is intermittent?

 

Maybe contact your local Honda dealer, and see if he has a TSB on it. Also talk with the service manager and see if he can help you since it's an intermittent problem, and you don't know when it's going to do it again (you might be out of town when it does act up). Just a thought.

 

Quick update: problem happened again. This time I cranked the heat up to full blast (both sides) and let it run for a couple minutes while driving. Then turned down to maximum cold and the problem disappeared. I tried this trick the first time I had the problem and it didn't make a difference but given that the problem is intermittent and disappeared when I changed the temperature, it feels more like an electrical problem to me, so I'm going to start by tackling the motor/servo that controls the drivers-side temperature blend door. Replacement part is about CAD$140. We'll see.

 

Today I removed the temperature blend door actuator. I only removed the actuator, opened it up, applied some dielectric grease to the gears and put it back. Since the part is $130, I'm hoping what I did might have solved any minor electrical issue. Of course, being an intermittent problem there's no way to tell immediately if this made a difference - I'll just have to wait and see if the problem recurs. Definitely check out the YT videos below to see how the part is extracted (videos of Accords and also the Odyssey which is very similar). Then start with a repair attempt. If repair fails, there's a very interesting video about using a Cadillac part for $15 instead of the Honda part as they are nearly identical. IMPORTANT: make sure you mark or photograph where exactly the white plastic piece is situated on the rest of the part before you take the actuator apart -- once you take it apart the white piece spins freely and you won't be able to re-install it because the male pins won't line up with their female counterparts in the dash. The cheapest option is to start with the repair, but bear in mind extracting and installing the actuator is a PITA as you have to pretzel yourself under the dash, and you'll need some source of light so you can see what you're doing. You might want to consider skipping the repair if you don't want to take the risk of having to replace it if the repair fails. I found by far the best position was to lie on back with both feet outside the car on the ground.

How to attempt repair:
Cheap Amazon/Cadillac option:
General removal instructions:

I also uploaded some pictures of the actuator guts: https://imgur.com/a/HIXojyl