A/C control module defective

The actuator could be defective. Look at your heater under the bonnet and look for a valve. Check to see if it has a vacuum hose hooked to it or a cable. Check to see if is working. Possible plugged heater hoses. Flush heater system.

Yes the blend door is what controls the air temperature at the register outlets. An example would be the temperature control is set to heat, but you only get cold air or slightly warm, then the blend door is not functioning correctly either due to the door actuator being defective or the blend door has become warped and is jammed, in most cases both are the problem. If you do have automatic climate control there can be a problem with the control module as well, but that is the rarer of the problems I have seen. This assumes the heater core is getting hot and it is not plugged.

Whole control doesn't work ?
No power for rear cabin at all ?
it could be bad connection.
I have friend freaked out "I have no power for whole rear cabin!! It was working !! somebody help! " at Emmy award Limo parking few years ago.
I looked at her limo, she did turn main switch off on overhead control module unknowingly. maybe she touched something else but accidentally flip rear main power off.
Is not the case ?

also, if your 2nd alternator burned out, you have no power for rear cabin.
But if it's the case, it remain no power for rear cabin (and outside coach light) until you replace 2nd alternator. It won't be "sometimes work sometimes don't".

I had friend who had bad connection (lose connection) at power switch (switching main battery and 2nd battery, it's engine compartment on top of passenger side front tire well)

do u mean the powertrain control module? if so it is located on the l/h side under the cabin filter housing. remove wiper arms, windscreen plastic scuttle panel, metal brace bar, caution. the 4 outer bolts can break off easily. and cabin filter housing , the module is held with 2 nuts remove connectors and nuts the module then comes out from inside the car remove footwell liner for access

think u need new switch or module-repair books for that model r available

Check for low coolant or rusty coolant as well as a defective engine coolant thermostat being stuck open and the engine not reaching proper operating temp. You can also have a problem with the door that controls hot and cold air to the cabin, it is called the air temperature control blend door.

Hi Manuel, That warning light indicates the coolant level is low. To attend the problem make sure the engine is cold. Open the filer cap and the bleeding nipple. Open the cabin heater control to fully hot and fill until all air bubbles have been evacuated from the cooling system (top up with the required mixture of water and coolant/anti freeze, about 40 percent coolant sixty water) When all bubbles have been evacuated, close the bleed nipple and replace the filler cap. Set the cabin temperature as required. If coolant is at correct level and system has been bled it is possible the sender unit may have become defective. Regards John

Hi James, If we're talking about the radiator for cooling the engine, check the thermostat and water pump. If we're talking about the cabin climate control, check the valve operation of the cabin temperature control. Regards John

This is related to the body control module, take it to the dealer and have it function tested.