Hello, I have a 1998 Honda Accord 4 door 4 cyl. I am having issues with the heat . It never seems to blow out strong heat although sometimes some will come out. blower works great. The thermostate has been changed, heater core flushed along with entire rad. system. Also, when the blower is not on and dial turned to full heat the air out of the ducts is at least warm. Not sure if something is stuck or where to go next with this issue. all seemed to happen when the AC system stopped functioning properly (blowing warmer air). I dont know if the heat dial is not working if it isn't mixing right, if something is not opening all the way or what. had many people look at it from general service to electricans and still no fix. any ideas would be extremely helpful as i need to get the heaat working or my little fgirls will freeze!!

 

The temperature dial is just an electronic control - all the work is done by little motors so nothing moves unless the key is ON.

First, check out whether the plastic **** is busted; check to see it's actually twisting the shaft.

Then you might have to remove a trim panel to get a look at the bottom of the heater unit. Look for the air-mix motor #6 in the picture.


When you turn the temperature dial (key ON) watch it; two different things are supposed to happen. It's supposed to move some doors within the heater air-duct housing. See if you can at least hear those damper/doors moving. If not, you might try dismantling so you can SEE the doors? (I never had to do this when I had a '98 so I'm a bit vague.)

Also it's supposed to push/pull on the cable #9 that goes out to a valve on the heater hose. If that doesn't move, maybe the cable is broken or disconnected at either end.

 

what trim piece would i have to remove in order to see the heater unit?

 

I am not sure which trim piece Jim is talking about.

I would look at the valve inside the engine bay near the firewall. It is driven by cable #9 in the pic and is attached to one of the heater core hoses. See if it opens/closes when you change the heat from high to low. Once the engine is warmed up, shut off the engine and try to feel both hoses that feed to the heater core (#4). They both should be at the same temperature if you have the heat set to high (from coolant flowing through it).

 

Alright checked the valve (it was on the lower hose) the linkage does appear to be moving dont know if that means the valve is working properly or that the cable is moving. Both lines seem to be the same temperature or at least close.

 

Point is, that motor moves not only the cable to the valve, but it also has to move a big plastic flap inside the air-distribution housing (the air-mix door).

Since the cable is moving, that means the motor is working and the cable is hooked up. But maybe there's a broken plastic linkage from the motor to the air-mix door.

I don't have the 1998 any more & memory is kinda vague. Try the panel below the glovebox. Maybe something on the side of the console, way forward. Or maybe you can get creative with an inspection mirror??

Anyway, if something IS broken, you might have to remove the glovebox itself, and the blower housing. That way you can see into the big square opening in that picture.