I have an 03 Accord coupe 6 speed,navi, etc.
Since cold weather the heater has been working intermittently. Cooling system was flushed about 3 years ago. I have taken it to the Honda store and then it works. They found no 'codes' on the system.

They recommend changing timing belt and water pump. They also would change thermostat, althought they didn't think that was the problem'
Nothing about the heater core, or any of the mixing valves, doors, etc. I don't think they know or have a clue as to how to proceed. Never seen such stupidity.

Anyone have an opinion about possible cause so I can take it to someone who just may understand what I'm talking about. Apparently Honda doesn't have a clue.

 

Well if there was a prob with a door it would've thrown a code, assuming they checked that there was enough coolant in it and there wasn't a leak i'd say the most likley culprit is a cloged heater core. A lot of times when shops do a coolant flush they'll put in some sort of "stop-leak" additive. Especially if it was a BG service or something equivalent. Anything like that will cause restriction over time, and three years is a pretty long time to run the same coolant anyway. So I'd flow test the core and see where you get.

 

Service was all Honda service. 3 years is about right for cooant change, IMHO. I can test the heater core, not sue why the dealer didn't. Didn't realize the doors would throw a code, that helps, thanks a bunch.

 

Yeah, as long as it has an hvac module. It may show up in the bcm as well, but since you have navi you prob have an hvac module. No prob , happy to help.