Hello. I have a question regarding the behavior of the climate control system on my 1997 Honda Accord. I had the controls set up to pull in fresh air from outside without heating or cooling it (A/C off, temperature dial all the way to the left, airflow to dash vents only) but noticed that the air coming out of the vents was warmer than the air outside. The ambient temperature was 60 (rather warm for a late December day in central Indiana) and I measured the vent output temperature to be about 75 at idle with engine at operating temperature, regardless of blower speed. I assumed that with the controls set up the way they were that I should get a vent temp that matches the outdoor temp or only slightly higher. I know the air mix door and heater control valve move when I adjust the temperature dial and I can successfully vary the temp coming out of the vents. I've read that it's possible that one or both of the two cables controlling the air mix door and heater control valve can be out of adjustment and might allow a slight amount of heat in from the heater core but I also understand that it's possible that the heat from the engine bay can get pulled through the fresh air intake at the bottom of the windshield along with the ambient air which would result in warmer than ambient air out of the vents. I haven't tried actually driving with the climate controls set up this way (I actually ended up using a mix of A/C and a little heat to achieve a comfortable temperature) but maybe if I kept my original setup while driving then that would bring the vent temp a little closer to ambient temp than it was at idle since there would be more air flow through the engine bay and less of the stagnant engine heat. So my question is should I expect the temperature difference I mentioned earlier or is there something I can do to lower the temperature difference? I'm trying to decide if it's worth it to go through the cable adjustment procedure when the cables might not even be out of adjustment and I might end up with the same results as before. Any thoughts on this would be greatly appreciated. Thanks!

 

The temperature control cable closes a valve on the heater house in the engine bay. You can try pushing the valve closed with the temperature set to cold in the engine bay to verify the valve is completely closed.

The other check is to remove the control dial, because those are known to crack and maybe the dial is slipping and not actually pulling the cable

 

My '97 has the worst A/C and heater performance of any car I've owned for years.
A friend has a '97, and from riding in his, his climate control system is no better than mine.

Hope you post up your solution, or efforts at solutions, or what you found didn't work - so others can benefit. Thanks

 

Pretty sure there's actually 2 cables. One goes from the control on the dashboard down to the air-blend door. The 2nd cable goes from there out to the valve on the heater hose. Have someone verify the valve actually moves when you turn the ****. If that's good, then you know both cables are connected. Maybe an adjustment so the valve is actually all the way closed when the temperature **** is turned to cold.

The car is 22 years old, so it's always possible the valve is broken and doesn't really shut off the hot water.

 

Thank you for the advice. I will try the test you mentioned at some point with the valve. The trouble is I will have to remove the intake hose to access the valve since it is buried under there so it will take some time but I should be able to find out one way or another if it is closing all the way. I know the cable is moving it because the valve arm is in two distinct positions for full hot vs full cold on the dial. The arm is pulled back towards the firewall on full heat and pushed toward the front of the car on full cold. Funny that you mentioned those dials getting cracked because I actually had to replace those for that very reason.

 

Wow! Good to know I'm not the only one experiencing unsatisfactory climate control performance. I actually had my AC system replaced with all new components and it performs no better than the original system when it worked. On hot days I have to have it on recirculate the whole time with the fan on full blast and even that takes forever to cool things down ESPECIALLY in stop and go traffic. I have to agree with the heating performance as well. It also takes forever to heat the cabin to a comfortable level on cold days. I like almost everything else about the car but it's a shame that Honda dropped the ball on the climate control system. It's better than nothing I guess. I will definitely let you know if I find something that works or doesn't work.

 

Thank you for the suggestion. I know the valve arm changes positions when I move the temperature dial. I haven't actually seen the valve arm in motion since it was only me testing it. I will get another person to move the dial so I can see the valve actually moving like you said. Maybe the cable to the valve needs an adjustment or it is possible the valve itself broken like you said and allows unwanted coolant into the heater core. I'm not sure but I don't think I have to adjust the cable from the temperature dial to the blend door since it uses one of the newer cables from that generation that only allows it to be clamped in the one place. The adjustment to the heater valve cable is definitely worth a try in case the valve is not fully closing and I will most likely attempt it. I just need a decent time frame to do it since I will most likely have to remove the air intake hose to access the valve since it's buried under there. Thanks again!

 

You know it's moving because it actually does change position. I didn't mean you absolutely need to see it in motion. When you turn the dial, is there any place where it's sticking or feels like it doesn't move smoothly?

When you remove the intake duct, see if it's easy to disconnect the cable from the valve's arm. Push the valve arm back & forth to show what's the limits of travel. Then you'll know whether the cable is pulling it "mostly" closed.

I never had a 1997, so I'm not really sure if it's possible for the blend-door to be broken somehow, yet the cable connections are still OK to drive the water valve in the engine compartment. Maybe that's something to check out?

 

I loved the heat my 97 made. The AC system left a little to be desired though. But in my case I had a Freon leak somewhere. If I charged it, it would work fantastic for a couple of days, then not really cool like it should. I really didn't feel like opening up the system to replace some o ring or something, so I just lived with until I sold the car (replaced it with my 99 Accord which has great heat and AC).

 

I actually do notice some increased resistance in the temperature control dial in an area around the middle range from cold to hot and hot to cold. It's easier to move when it's near the cold and hot positions though. I think the blend door is fine because I can hear an audible thump if I aggressively turn the dial to full cold or full hot which I read I am supposed to hear as a result of it fully closing or fully opening so I think that it travels through its full range. The interesting thing is the valve seems to have a shorter range of travel in that it takes several clicks starting from either side of the dial for me to notice it moving in the engine bay. Maybe that increased resistance in the middle area of the dial I mentioned earlier is a result of the valve actually moving. If I had to guess, I would say the valve is moving through its full range by the looks of it, and the fact that the dial is moving through its full range along with the blend door seems promising. I won't know for sure if the valve cable is actually in adjustment until I test the limits of the valve arm with the cable disconnected like you said and compare that with the positions it reaches with the cable connected and dial turned to full cold or full hot. I will actually be away from my car for the next week as I have flown south for winter break but I am eager to try all these things when I get back.