Hi all,

I'm trying to diagnose a low heat issue in my 98 EX V6. I suspect that there is a problem with either the blend motor or the mode motor. The Haynes manual shows a diagnostic using the AUTO and OFF buttons, but I'm not getting any result using it.

(It's the same sequence as described in the fifth post in this thread https://www.hondaaccordforum.com/forum/general-tech-help-7/honda-accord-climate-control-diag-codes-39789/)

My climate control looks like this one:


Are there any other diags to use for the automatic climate control? Or am I missing something?

Thanks,
Tyler

 

Maybe one of our members will see this and chim in to an answer for you..someone in here may have run into that problem somewhere's back down the road..

Good Luck with it.
WheelBrokerAng

 

So the "segments" do nothing? If so then there are no codes.

For low heat, what you need to do is check the heater control valve for proper movement and that the cable is attached.

Next would be the blend motor (this one "blends" the hot and cold air) for movement.

Last, be sure to check the cabin air filter.....no sure if "low heat" is meaning low air flow?

 

I never see any segments. When I press and hold OFF (while also holding AUTO), the display goes blank and never displays 88 even if I hold both buttons for a minute or two.

To be more clear about the root problem, I have good airflow but it seems that the air coming out of the drivers vents is a little hotter than the passenger vents. So I suspected a problem with the blend motor or mode motor, which I am trying to diagnose. I don't know how to get to those motors through the dash so I was trying diagnostics. The only dash work I've done was a radio change and to change cabin air filters.

What I've looked at so far: Coolant level is good. Heater control valve is operating properly. Both heater core hoses are hot so I don't think there is a blockage. I drained the coolant, flushed the system, and refilled with Honda coolant (it was overdue). I flushed from the radiator as I was in a time crunch to get everything back together and I wasn't able to get the heater core hose off. The thermostat is doing what it should and the engine is coming up to temp in a couple minutes and maintaining temp ok, but I replaced it anyway since I was in there and the car is 15 years old.

So, all that said... what is the best way to check the blend motor? My Haynes manual doesn't really show where it is or how to get to it.

 

Do you hear a rattling sound from beneath dash?

The air mix motor is a frequent source of blend problems and noise. The feedback variable resistance gets clogged w/ carbon material from resistance strips and confuses the controller. Also the drive can fail. See following post on another forum and link to youtube video for explanation. The air mix motor is similar across vehicles w/ ATC.

Rattling Center Dash (Heater A/C Air Mix Motor) - Acura MDX Forum : Acura MDX SUV Forums

Air mix motor appears replaceable in this model. Suggest purchasing a download manual for your vehicle from automanualsource.com for $22.

good luck

 

No rattling that I've noticed. Thanks for the link and video, I'll check them out and report back.

 

Does anyone know where this blend motor is? Or which panels I need to remove to get to it?

 

Air mix motor appears (in shop manual diagram) to be directly behind the heater/AC control panel.

Manual does not describe any items required to be removed for access. It may be accessible from under dash.

Manual does describe diagnostics to determine if motor is working correctly.

good luck

 

Is the manual you're referring to the one from automanualsource.com? Seems like it has a lot more detail than the Haynes one I have.

 

Yes, it's an efile, Honda Shop Manual.

good luck