First time user here. Be gentle with me.

I have a 99 accord lx coupe 4 cylinder.

When I turn the air on (from low to high), I can hear the motor working with air coming out from the driver and passenger side vents but nothing from the center vents.

I replaced the cabin air filter hoping that will it will fixed the problem but still no air from the center vents.

Any ideas what the problem could be?

 

What happens when you switch the mode from vents to defrost, to floor, etc... Will the air keep coming out of only those vents, or does it switch?

 

Passenge and driver vents have air coming out for all the modes. The defroster has air coming out also. Very slight hint of air coming out from the center vents.

Noticed no air from the floor when switched to floor mode.

 

Does this have Auto HVAC or manual controls-push button?

 

You mean climate control? No. Setting on the left **** is from 1 to 4.

 

Here are the basics of the mode control system.

The mode control motor is under the dash. This is based on my 95 accord, but yours will be similar.

The mode control motor will have around 7 wires going to it. The motor will get voltage on one of the wires when the key is in the II position at all times. One wire will always have ground. One other wire will have ground depending on what mode is selected on the dash. The mode control motor change the routing of air through the system depending on which mode is selected.

Your problem will be either the mode controls on the dash, the wiring, the mode control motor, or the internals of your heater unit.

The best place to start will be the electrical connector for the mode control motor with the key in the II position. You will need a volt meter to figure out which wire is getting 12V to ground.

Then find the two wires that have ground. Switch the control from to something different like the floor. See if one of the wires that had ground is open to ground. Another wire should be grounded. The next step in diagnosis depends on what you find on this step.

I would suggest getting a shop manual for this job. I got one as a pdf from automanualsource.com for $21.99 for my TSX and it is a good investment. It will show you the wire colors and will make testing quicker if you know how to read wiring diagrams.

 

I found that cycling through the vent selection buttons leaving the center vents as the last position worked to turn my 94EX vents to center. It's done this for some time, but not sure why. Easy enought to try.

good luck

 

Again this in on the 5th gens. What I have found it the "slide levers" get dry and that makes it hard for the motor to move them. A slight push and then they move. From the drivers floor board, look up at the center dash area and you can see the plastic levers/slides....again this is from the 5th gen (94-97). I add a bit of lube to the slides and things are good for another 6~9 months...must be using the wrong lube