AC/Heater - 1999 Honda Accord LX

You may have an inoperative door in the system.

Most are vacuum controlled.

Good luck.

Check with some Honda forums.

You might need to replace the t-stat control.....

http://www.ebay.com/bhp/99-honda-accord-ac-control

http://www.youtube.com/watch?v=Lg9rDOOqvIA

You might have no heat transfer fluid. You might have a dead budgie in the air ducting. I can't quite see it for myself.

It's not dead, it's pining for the fiords!

you have one of these in your duct system

The system in your Accord is very simple. You have a box where the air comes in (either fresh or from the cabin), two heat transfer devices in the box and heated or cooled air coming out of the box. The air that comes out of the box goes through duct work via damper doors that open and close - lets air go through different ducts. The control is done either by electric motors or vacuum (I think yours is an electric motor). A controller tells which motor should open or close (your air conditioner vent controller on the dash). You also have manual vent controls at the vents themselves.

If you're not getting heat or air conditioning, you need to find out if the duct system is working. If you feel air coming out of the correct duct (and not the others), the duct system is fine. If you are not getting air to come out, it could be either a clogged duct (something could be inside), a blocked intake (too many leaves) or bad actuators (sending the air to the wrong duct). Or it could be that the motor turns, but the fan blades don't move (very unlikely).

If you are getting air to the right place, then it's the heater core and the air conditioning evaporator. There is a water flow valve, which lets hot water into the heater core. If this valve goes bad, it will either completely block the hot water flow (no heat) or stay open and have hot air when you don't want it. Yours would be the blocked hot water flow problem. So why no cold air? Could be that your a/c system has a leak and it's just coincidence that both seemed to go out at the same time. An easy way to check this is to open the hood, start the engine (with the air conditioning off) and then turn the air conditioning on. The person under the hood should hear a fairly loud click (the compressor being turned on via the clutch) and the noise of a pump (could be pretty quiet or may be pretty loud - depending on the wear). If this doesn't happen, then most likely you have a freon leak or a bad a/c compressor. The evaporator will usually not go out.

It's borken?

Are you getting air flow from the vents?

Someone miss label the car it's really a Chevy Cavalier.

The problem you describe involves two systems,with only major one common

component:The fan and ducting from the fan.If you have no airflow from the vents,

but hear the fan running, the problem is in the pneumatic controls that operate the

airflow diverters.If you have airflow, there is one thing I can think of that will do this:

The thermostat sends a signal to disable the A/C clutch if the motor gets too hot,this

could cause the A/C not to work.The engine could be very low on coolant, which

would not not provide enough coolant to circulate through the heater coil,or keep

engine cool.This could cause both problems.

Believe it or not, I have seen this happen.The coolant recovery vessel was full,so the

owner did not check the radiator,presuming it was full.But the recovery system has to

be air tight to work properly.

A small leak in the cooling system(Water pump,radiator,hoses,etc.) will drain

the coolant, and the system will not pull any fluid from the recovery container

because it has lost vacuum when cold.

Check coolant level in the radiator.If all is ok,problem is in the controls.

Maybe stuck flapper door, as mentioned elsewhere.Not fun to access.