BigG422

Ill try to explain as best I can but hopefully this is an easy fix. So I've been having a problem where in the morning I turn the temp to heat and the front window defroster to defog the windshield. Then once I'm done defrosting I turn the temp to cold but the temp remains on heat. I have have tried switching the temp back and forth, changing where the air is venting out of, switching the AC on and off and nothing.

I will say that otherwise my AC working perfectly fine and is cold. The AC light is always on when this issue with the heat comes on. The weirdest part is when the car is off overnight, or an extended period of time when I have to defrost during rain, the AC will be back to work fine.
My guess is its a relay but I tried tapping and removing the AC compressor relay and it does nothing. I will say that the compressor sounds like its on the entire time this issue is occurring. Its almost as if the thing that switches from heat to cold is stuck or something. Any ideas.

CraigW

iTrader: (1)

When heat stuck on, you can look at the valve under the hood on firewall near top I think it moves 90 degrees. (blue cable)

I set my Honda systems to be able to release the compressor, don't want or need it running.

ezone

Does this mean all of the controls become inoperative?
7th gen uses servos, electric motors to control the air temperature, vent/floor/defrost positions, and recirculation mode.

Turn the key on but do not start the engine.
Turn off everything in the car, radio, lights, heater fan.

Listen carefully.

Push the recirculate button and listen for the noise of a small electric motor running for a few seconds.

Turn the vent/floor/defrost mode dial and listen for the noise of a small electric motor running for a few seconds.

Turn the temperature dial and listen for the noise of a small electric motor running for a few seconds.

Can you hear all 3 operate?
Try this when it's stuck on heat and see if you still hear all 3.


Try running the HVAC panel self diagnostic test. (may not be helpful if it's working when you do the test.)

BigG422

I will try that but to answer your other question, yes the other controls still work fine.

BigG422

So I tried what you said and when I turned the temp one from cold to hot it gave a slight crackling sounds and then stopped being responsive. I turned the car on and sure enough it was stuck on heat. I also noticed that when I tried it again with the car off I hear nothing running as I try to turn the temperature ****. The other two ***** works fine and I can hear the motors running when I change the functions. I will also say that I had been noticing that crackling sound for some time now when I turned the car on in the mornings but didnt think anything of it because it would stop making the noise after a couple seconds. I also did the self diagnostic and recirculation indicator blinks the diagnostic trouble code of 9 blinks. With that in mind, what needs to be replaced?

ezone

Code 9 is 'a problem in the air mix control, linkage, door, or motor'
Probably detected that it is not in the correct position.
(Duh, we already know this.)

What I would do next is remove that motor from the HVAC housing in the dash.
Reconnect the wires and hold the motor in your hand.

Operate the HVAC controls to make the motor run both directions several times, and then try slowly moving the control a little at a time so the motor has to stop mid-travel several times. Apply a little pressure with your fingers to make sure the motor can actually push and pull on the linkages in the dash with a little bit of force.

If it quits working at any time, you need to figure out why.
Motor problem? Position sensor problem? Control panel problem?


But if it never quits working in your hand, then go to the linkage where you just removed the motor and operate all of the linkages by hand, feel for any binding that would stop the motor from moving.

========================

7 wire connector, 5 wires in it

2 are for the motor operation, pink/blue and green (terminals #1 and 2)

3 wires are for the position sensor
voltmeter test: Motor connected and operational: Backprobe wires #3 and 7 (pink/black and light green), you should see approx 4v at full heat and approx 1v at full cold, and smoothly changing as the servomotor moves throughout your testing.

BigG422

Any guides or tutorials you could point me to on how to get the hvac housing out? I'm not afraid to get my hands dirty but need some sort of guide to help me get me on the right path to try your suggestion.

ezone

Getting the HVAC housing out would mean pulling the dash out, I'm pretty sure you don't want to do that yet LOL

Just find the servo motor and take it off.

Listen for it! Watch its linkage move when you make it work.

Drivers side of the dash, stuff your head in the footwell area and look up above the gas pedal area. The motor is directly above the cable with a green plastic wire plug on the bottom.
The cable you should see is connected to the linkage for the air mix motor, and that goes through the firewall and leads to the water valve.

rallyeredem0

happened to me once and i just swapped the dash controls from a used junkyard piece, solved my problem