2003 Honda Accord EX v6 dual climate control.
If you turn up either thermostat to get heat, the fan will increase in speed, as it should but still blows cold air UNTIL you turn to max heat, then the heat comes through and continues as you turn the thermostat back down until you turn to LO then switches back to AC. In other words, it stays on either heat or cold until thermostat is turned to max heat or max cool. The water valve allowing the hot water to flow through heater core only moves when either thermostat is turned to max heat or max cold. I would appreciate some wisdom on how to repair this problem.

2003 Accord EX 3.0
Romak

 

I'd start by checking for HVAC codes?

There is a "how to" in the sticky at top of this section....Common DIY and Info. Threads

https://www.hondaaccordforum.com/for...threads-40780/

 

Sounds like a problem with the in-car temperature sensor. Unless the temp sensor tells the HVAC what the temperature is, inside the car, it doesn't know whether to heat or cool. That is, until you go to full hot or full cold, when it will override the temp sensor.

 

Thanks Poorman & Nighthawk

I retrieved the error codes. The center bar on the first 8 (which I believe is "L") and the lower right bar on the second 8 (which i believe is "J")

I cannot find any descriptions for the codes.

I would very much appreciate your help.

 

J is a short in the air mix control motor circuit (probably your issue) L is an open or short in the mode control motor circuit. (controls where the air comes out)

 

Thanks,

Any idea what needs to be replaced?

 

is this issue intermittent or does it happen all the time?

you could google all the required test's for the air mix motor circuit, or you could just find it, pull the connector, check for any damage and plug it back in and hope for the best. or you could replace the mix motor itself. mine did the same a while back and hasn't done it since.