2002 Honda Civic LX Air Conditioner

I purchased this vehicle new. My Honda’s compressor was replaced at a Honda dealer in September 2011. In June 2012, when the weather warmed, the car’s interior was markedly uncomfortable, UNLESS I was on the highway doing speeds of 50 or better. Took it back to the dealer a number of times, to no avail. I purchased a temperature probe, and stuck it in one of the vents. Temp. of air was 44 to 46, at best.

A couple of weeks ago, with the A.C. OFF, I noticed warm air coming out of the vents with only the fan on AND the temp. control all the way over to the coldest setting.

Question: Is there some kind of an adjustment to whatever controls the mixture of hot/cold air - baffle/whatever - that will completely shut off any heat from the inside radiator?

Thank you.


There is a blend door that controls the flow of warm and cold air under the dash. Honda’s of the error have AC compressor problems. I have 2 friends that had their AC’s die and the whole system had to be replaced.

Step 1. Is your a/c working? You need to have system inspected. Is compressor working and producing acceptable pressures? If it is, than you look at air blend door issues. All cars have a/c evap under dash. It is similar to your heater core. So you really have 2 small radiators under dash. 1 for heat, for cooling. The air blend doors are operated by electrical motors on some cars, vacuum operated motors on other cars and even cables that are attached to levers on older cars. You need to find out IF your system is working. We cannot guess if it is or is not.

There is a hot water valve in one of the heater hoses under the hood. It is operated by a cable that comes from the blend door under the dash, and that in turn is operated by a cable from the heater control panel.

Heres the problem, the heater control valve handle is inline with the hose in the off position instead of the conventional perpendicular position, and the cable pushes it closed. Pushing with a cable is not as effective as pulling it and if you are familiar with trigonometry, you will know that pushing an arm from an almost parallel position takes a lot of force to move it. In other words, it is almost impossible for that set up to completely cut off the hot water supply to the heater core.

This has been a design defect on Honda’s as far back as I know. Honda are you listening? On our Honda, I just open the hood at the beginning of summer and manually finish closing the valve. This works as long as you don’t touch the temp control in the dash. Unfortunately the newer Honda’s with climate control will open that valve for you so if you have climate control, you are out of luck.

Uh, ok. Thanks for a/c theory lesson. IS a/c working? A dealer usually has smart a/c techs. Maybe try another shop?

Yes your AC is working, but it is fighting the heater. Yours is actually working pretty good as the best (coldest) air you can expect out the vents is about 40°F. 44-46°F is pretty good unless it is only 40°F outside.

I just want to thank everyone who responded for their comments and suggestions.

Keith: Just so you know, there are no cable controls in this 2002 Honda Civic LX.

Cavell: The A/C is working. I am going to take your advice and bring it to another shop, before summer arrives.

Again, thanks to everyone. If a solution is found, I’ll be back to post again.