mrsrubis

I have a 2007 Honda Accord and as of today the heater is no longer blowing hot air. The defroster still blows hot air and I have checked the fuse but it is not blown. Ideas please?

redbull-1

Turn the fan blower to the highest setting, does it blow hot air now?

Targa250R

What trim level is this? LX/SE/EX with manual HVAC controls? EX-L/EX-V6 with automatic climate control?

Is the blower blowing at all? Does the direction of the air from the vents change when you select a different mode (e.g. upper vents, floor vents, bi-level, floor/defrost, defrost)?

sncobra331

check the hot water valve
it is located on the passenger side of the engine bay near the firewall.

have someone turn the temperature hot to cold and see if the lever moves.
These also tend to break and leak coolant.

EDIT-I misread the post... if you are getting any heat in the vehicle it's most likely not the
hot water valve.

S2Knimgone

I have a 2007 Honda accord ex 4 door 3.0 6 cylinder i have no heat I've changed the heater core the thermostat and it had been flushed and filled all air purged of system and still no heat need some help

Frank Howard

In my 04 accord I had a similar problem where my vent didn't blow at all. Not sure if my fix will work for you but I replaced the resistor for the ac blower. It was actually a really easy fix and I did it in the parking lot of advanced auto. That way if it didn't work, I could simply return that part which was around $60. There are several videos on how to do it. Here is one of them.


Good luck!

S2Knimgone

It blows air just cold when you turn the temp from hot to cold the cable inside the engine bay moves so that works changed everything else *** will heater core thermostat and flushed the radiator will is AC blower resistor have something to do with hot air blowing

Frank Howard

Not sure if the resistor is the culprit, sorry. In my case it worked, bit I had no air blowing at all. It may be worth a shot and if it isn't it, just take it back.

NightHawk92

should probably check the air Mix control doors there electorally controlled so its possible the motor went bad inside and is not moving air though. And look at the linkages to. It would help a lot to get the Factory service manual. Gives a good expiation on how the Dual zone climate control system works. best money I ever spent on those maunals.

Bamm

my ac works but when i try to turn it on heat its still blowing cold air can u help me out

Accordian47

There are several electric motors or actuators mounted to the HVAC box (big plastic box under dash that houses heater core and a/c evaporator). There are doors that are inside the HVAC box, they are moved by the motors to change things like the direction of the air or "Mode" you want the air to come out of. They are also used to operate whats called the "heater valve" or "temperature control valve". This valve is a small plastic valve that is mounted in the engine bay, it has an inlet, an outlet & a small metal arm that is operated to open or close it. It is mounted in-line with the supply hose that supplies hot engine coolant to the heater core. The heater core is the heat exchanger or mini little radiator that is mounted in the HVAC box that delivers hot engine coolant for heat. The motors are operated by the climate control panel when you press a button or when you set the temperature on automatically controlled climate systems and the system needs to make an adjustment. The motors are fed power through the climate control panel.

If you set the temperature to full heat but your still getting cold air...then it's time to check the motor that controls the temperature control valve. You can identify which motor on the HVAC box is the motor designated for temperature valve operation, operate the temperature controls from hot to cold several times back and forth and observe the motor. If its turning or operating then you can eliminate a large part of the troubleshooting procedures because you now know that the actual climate control panel and its electronics are operational and that there is power getting to the motor. You can also eliminate the motor itself but not entirely, you know the electronics side of the motor is working because it operates BUT internal to the motor's housing is a set of plastic gears designed to reduce the torque needed to operate the actual heater/temperate valve. It is possible then that the motor is operating but that these gears have become damaged meaning your motor works when you select the temperature, the climate control panel and its electronics are operational BUT the actual temperature is not being changed because the internal motor gears are damaged and the valve is remaining in the cold position. Another thing to consider is the actual cable that is connected to both the temperature control motor and the heater or temperature valve. It connects to the motor and is the link between the motor and the actual valve. It could be broken or damaged or have a high resistance due to a kink or corrosion.

Accordian47

This is a diagram I made that outlines the different parts and how they connect to eachother:

This is a oem Honda parts diagram of the HVAC system. Note #7 in the illustration, it's circled in red, it's the motor that operates the valve:

Accordian47

If your defroster is blowing hot air then you know the heater core is getting hot engine coolant and you know the blower motor is good. The next thing to check is the operation of the climate control panel itself and the HVAC box's "mode control motor & door".
When you select the different "modes" (which vents the air comes out of ex. floor/ floor & defrost etc.) does the air come out of the correct vents? Temperature aside, does it correctly change which vents the air comes out of when you select all of the different modes?