I have a 2005 Honda odyssey. When I turn press the rear A/C button, the whole A/C system blows warm air and the a/c doesnt get cold at all....Is this a clogged hose or something??...

Give passenger a blanket

may be high pressure switch is bad. accumulator or expansion valve may be clogged. may be low on freon. clutch could be bad on compressor. take it to shop to get it checked.

HVAC Vent Doors under the dash- need to be diagnosed
One is not operating- to switch the air flow
HVAC Vent Door Motor or Vacuum Motor
which ever type you have

Check if the compressor is working.
looks like there is a problem with compressor , hence working intermittently.

I've have never heard of a "only cold air system", but hey, nothing surprises me anymore. try replacing the control unit in the front. hopefully that will take care of the problem. If not you need to check your blend valve. (headache depending on location)

Since warm air eventually comes out when the vehicle is in motion, you may have an air mix door that is stuck in fresh or is somehow blocking warm air from the heater core.

To see if the air mix control motor is bad, you need to retrieve your Diagnostic trouble codes (DTC's) from the heater control panel. To run the diagnostic function, do the following:
1. Turn the ignition switch ON (II).
2. Turn the fan switch OFF.
3. Press the recirc control button to select Recirc (recirc light on.)
4. Press and hold the recirc button to select Fresh (recirc light off) and continue to hold the button down until the recirc light comes on for two seconds and then goes off.
5. If the system is okay, the recirc light stays off.
6. If there is a problem, the recirc light blinks the DTC to indicate the trouble. One blink=a problem in the air mix control motor circuit. Two blinks=problem in the mode control motor circuit
Three blinks=problem in evaporator temp sensor circuit.
7. Turn the ignition switch off to cancel the self diagnosis function. Run the diagnostic again after repairs are complete.

Note: the air mix control motor has a rod which connects to a plastic link. The link controls the mix doors and also connects to the heater control water valve via a cable. The air mix motor may check okay, but if the link is broken then you will still have problems. the motor is on the bottom of the heater unit in the front passenger's foot well.

you are bodging it and as you dont know anything about the A/C system then leave well alone and get it done with a machine.the whole system needs to be evacuated oil drain needs to be measured then refilled with the correct grade of oil and then regassed with the correct WEIGHT of gas and possibly a leak sealer added using special equipment.If it still doesnt work properly then it needs draining again and the venturi valve removing and checking out on the front unit.This is a specialised job for highly skilled operatives with the right equipment

Hi Moonaw,
Take the vehicle to an expert on AC and ask them to check the gas pressure. If that's ok, then have the evaporator (that's the thing that looks like a small radiator which is the heat exchange unit inside the cabin. also have them check the expansion valve for the rear compartment...The fault must be in that section as the condenser, dryer and compressor are common to both front and rear outputs.

Best regards

Johngee10

Hi, my best advise is to have your air check for freon leaks ,low freon causes the compresor cluth to stop working ,this can cause the air to blow hot .......