I have an 03 Honda accord. No heat coming out my vents and temp gauge in car is reading normal. I have installed new thermostat and a new radiator. Inspected all hoses for cracks and leaks and they seem to be good. Checked fire wall to make sure wire on heater control valve is connected and moving and it looks to be good. Hose going into and out of heat control valve is hot. Top hose coming out of heater core is not hot though. So I have hot going into heater core and only warm coming back out of heater core. I have been trying to bleed air out of system by raising the car up on ramps and removing radiator cap then idling car between 1500-2000 rpms and still nothing. I even tried flushing heater core from both ends with garden hose to try and push out any air or any dabree. Still no Heat!!!!! I am stuck. I also ran the HVAC system self check. I found the drivers side 8, the top right line flashes. Don't know what error that means because cant find code explanation anywhere.

 

Read posting rules about not posting in DIY forum.

Code is open in sunlight sensor circuit; unplugged, wire broken, or defective sensor.

If you intend to DIY, you will need a multimeter and understand how to use to detect an open fault in wiring from audio/hvac display panel connector and sunlight sensor. A factory service manual is necessary to understand wire colors, pin locations, etc. See automanualsource.com for a $22 download manual.

good luck

 

Sounds like the mixing valve is stuck closed. You can try manually opening it and see if you get heat.

 

I appreciate the feedback. I am going to check on that mixing valve. ill attempt anything so I will see what I can do about the sensor. Thank you for the info

 

What is the purpose of a sunlight sensor?

 

Try turning the heat on and off and watch the heater core control valve and see if it moves properly. If not then there is likely an issue with the motor that drives it. HVAC code 8 on Hondas usually means a problem with the evaporator temperature control sensor, but I have not looked at the book for your car on this so take that for what it is worth.

 

It sounds like your car has auto-climate control HVAC instead of manual HVAC. The trouble codes are different between climate control vs manual A/C. HVAC number trouble codes are for cars with manual A/C. The HVAC alpha trouble codes are for cars with auto-climate control.

It is not manual A/C trouble code "8".

The trouble code you have is either "C", "D" or "F", depending on whether it is the left or right driver's side temperature indicator. (See attached image.)

C is an open in the outside air temperature sensor circuit.
D is a short in the outside air temperature sensor circuit.
F is short in sunlight sensor circuit.

If it is the outside air temperature sensor is located behind the front bumper (near the air duct). It is not the same as the sunlight sensor or evaporator temperature control sensor.

 

I wrote-up this thread a while ago that should help.

https://www.hondaaccordforum.com/for...-code-s-34589/