kipmcdowell

Hello folks,

My daughter's car has developed a no heat issue, just blowing cold air. I found the valve and lever assembly under the hood, and found that it is not moving when I adjust the heat/cold control from the dashboard. I disconnected the valve control cable and manually pushed the lever back and forth, but the position of the lever did not change anything. It appears that I might have two problems. 1) the control cable is not working. 2) the valve, while functional, is not diverting hot coolant into the heater core.

I am not having difficulty with the thermostat, the engine temp is steady and has been forever.

I am assuming the electronic dial is no longer working, because a couple months ago, I couldn't turn the heat off on a warm day.

What would be the next best troubleshooting step at this point?

holmesnmanny

Feel the hoses coming into and out of the heater core. See if they both get hot when the car is warmed up. If not, it's possible the heater core is clogged up.

fcm

Remove water valve and confirm valve is actually opening, not uncommon for lever to move but valve not opening, then refill with coolant and don't forget to bleed the system. 94

user456101

If none of the previous suggestions works I would guess it is the AC/Heat controller in the dash. I've had to replace mine several times. You can get one cheap at a junkyard and see it that fixes the problem. If it doesn't you can usually return it and get your money back. There are YouTube videos like "Hot to replace AC control assembly Honda Accord" and others on how to remove/replace the temp controller on this car.

kipmcdowell

OK, so I am narrowing it down. The water valve is stuck in a closed position, and once I manually moved that to the open position, I could feel both hoses get very hot. So that confirmed the heater core is not plugged. However, even with the hot coolant flowing, no hot air coming from the blower. So I am now thinking the temp controller is bad. I am not sure what this is or where it is, but I can easily get a replacement from our junk yard, they have 10-12 of these cars. Am I looking for just the panel and hot/cold dial, or is there more than that. I read somewhere a servo controls the cables that are connected to the water valve and air gate.

user456101

You are looking for the whole controller. That is the smallest replaceable unit. You can replace light bulbs or **** or buttons within a controller but you can't replace any of the electronics. What you are looking for can be found in YouTube videos like the one I mentioned in my previous reply. This one is more detailed "'98 - '02 Honda Accord Coupe Heater/ac controller replacement" It is the same unit in the coupe as it is in the sedan so don't let that throw you.

kipmcdowell

I swapped the heater control panel from my son's 2000 Accord V6 into the 98, and still no heat. His car still has heat, so the heater control panels in both cars are good. Now I think I am looking at the servo(s) that run the air gate and water valve. I know the water valve is not moving when I adjust the heat dial, and since the heater core is passing coolant OK when the valve is manually opened, it seems that the air gate is stuck in the closed state, which would make sense because the water valve is also stuck in the closed state.

kipmcdowell

I found an air/blend heater control actuator at our local pick-n-pull, installed it and now have heat. Thanks all for your help.

kipmcdowell

After I installed the new actuator, which was from a 4-cylinder car, I couldn't turn the heat off. It was really warm at the coldest setting and very hot at the highest setting. It seemed like the air gate/door that would keep the hot air out of the car when set to cold was not fully closing. After sleeping on this (and not relishing the prospect of going to the junk yard again to pick up an actuator from a V6) I remembered that I had swapped the control panels on our two cars, between the 98 and 00. After switching them back, the problem was solved. So it seems that there is something subtlety different about how the 98 and 00 heater control panels work. Now we are fully operational, and again thanks to those who replied.

Brethren

I had the same problem, no heat in the front, but rear working okay. Turned out to be the heater control valve stripped plastic under the actuator arm. The valve is located right side on the firewall engine side. Honda part number 79710-S3V-A01, valve assembly, water. Thanks to all for posting, you saved me a bunch of troubleshooting.