hi all, Im new here, I did a search a week ago, and did not come up with anything really helpful. I decided to join, to post this question, and maybe one of you all have had this problem before. below is all that has been changed out with new parts.

Ok, she has had the heater control valve bypassed. the heater core flushed, thermostat replaced, and all fuses checked. the AC will blow cold, but the heat does not work. it will blow warm air for a few seconds then goes back to cold. the girl has been driving with a blanket in the winter. it is a 99 honda accord V6, with the electronic climate control. the blower motor works in all settings, the control **** on the dash changes the temp settings, and the air will blow warm for just a few seconds. the heater core has been flushed and checked "good". but you can hear some water "swishing" around sometimes on acceleration, in the heater core. Is there another "valve" on the engine block that controls the water flowing to the heater core, that could be stopped up? thanks for any replies in advance. we are stumped.

 

Check the two heater core supply lines under the hood. There should be a valve in supply line that controls heated coolant flow to the heater core. When you have "no heat" check the supply/return lines. Supply should be hot/warm and return cold. This would indicate the heater core control valve is closed. You should be able to manually force the valve to open. Either it is not being closed by the Auto Temp Control system, is incorrectly connected, or is faulty.

good luck

 

hey thanks for the reply. they removed/bypassed that control valve. the car should be burning up with heat. it is a straight shot from the engine block to the heater core. yet there is still no heat. the only thing I can think of, is it has to be a control motor, in the climate control "air vane". not letting the air blow past the heater core. but even then, the cabin should fill up with some heat from the heater core getting a constant flow of hot water. if so, honda really insulates the climate control VERY well. the car belongs to a girl I just started dating, and she has been without heat for 2 years. I am "going in" behind her mechanic that bypassed the valve last year, and charged her 200 bucks to do so. still with no heat.LOL I was just going to try and get this fixed for her before it turned cold. I did not know if this might be a common problem with the Accord of that year model, and could get a "quick answer" :P. thanks for the help though.

 

Have you checked that both hoses are hot? If hose w/ valve is hot and other hose is cold there is no coolant passing throught the core. Reason may be blocked core due to trash or excessive "stop leak".

If heater core is definitely flowing coolant, then problem is blend door not being controlled by ATC. Most likely reason is faulty blend door motor,misrigged, or damaged wiring/connector.

A manual is essential to run a problem like this to ground.

good luck