Water jacket Heater gets cold at a idle I was told its the water jackets but I dont know where they are

Is the CAR overheating or the air coming off of heater getting over heated?

double posted.
you can hear the engine, driving with doors and hood closed?
i think you meant you can hear water from the cab heater.
my best guess.
that means the cooling system is low. (AIR in the water jackets and cab heater)
on a dead cold engine check fluild level of the actual radiator (cap off)
BINGO , no water to be seen?
all done dead cold or there is danger of scalding water.

Replace radiator water by adding coolant

you may have to flush out the motor and raidiator. check to seeif your water is not rusty if so that means you need to flush the motor . some times maylead to clogged water jackets in the motor.

Sounds like your heater core could be blocked up or a blockage in the pipes. Most car heaters run off a heater core that cycles hot water from the engine's water jacket, or a heat exchanger around the exhaust manifold, through the core, with a fan then blowing this hot air through the vents to you. If the pipes from the water jacket to the heater core are blocked then no hot water will get through. Alternatively, the heater core or pipes may be damaged and leaking. Check to ensure you're not losing any coolant. If it's the heater core, there's really nothing for it but to replace it. I'm not 100% sure where it would be on your car, on my old car it was up behind the centre console, under the dash. Hope that helps. Cheers, John

usually if the core goes bad it fogs things up and stinks bad'

You may have a head gasket in the throes of failing.
Some of the symptoms are coolant loss, rough running when cold (a small amount of water is sucked into a cylinder when it cools down), above average coolant temperature (causing the fan to run on). When checking your oil, pay close attention to any signs of discoloration and sniff the coolant overflow bottle for traces of exhaust fumes.
The gasket can fail between different points; cylinder to water jacket. This causes higher than normal coolant temps and can cause hard starting and rough idle when cold. If this point fails, the combustion can force hot gases into the water jacket and then sucking in some coolant when the motor cools down. The latter can cause cold-starting problems and stalling until warmed up and free of water in a cylinder.
Oil passages to coolant jacket; oil is under higher pressure than coolant which can force some oil into the water jacket. When severe, it can make Jergen's Lotion out of the oil (that doesn't help lubrication) and discolor and lend odor to the coolant.
If you don't mind dirty hands, I would remove each sparkplug from the cold engine and look for signs of rust or even dewy coolant deposits on the base of the plugs; been there, seen that.
Unfortunately, a failing head gasket won't set any error codes until severe enough to cause other problems to monitored areas.

often the head gasket breaks down between the water jacket and a cylinder .. the simptoms will be loss of water but with no leaks ... the heater may quit working at idle because of gas bubble accumulation (starts to work at fast idle) .. water out the tail pipe that smells like antifreeze is a sure sign .. if you want to know which cylinder is involved ... then observe each spark plug (marked for which cylinder) .. one will look different if its been exposed to the water .. you can also do a compression "leak down" test .. sometimes you will see bubbles or foam in the radiator (careful when hot) ... milky oil is a bad sign that water has gotten into the crankcase .. some heads are held down with special "stretch" bolts that can only be used once and require special tightning procedure .. dont try to retighten .. if you problem does not involve water loss then explain more of your simptoms ..

It's possible you have a bad vaccum line to the actuator door in the heater assembly
or possibly a stuck thermostat

you are correct - its called a heater control module,mounted on heater case under dash - i believe it is only available at dealers,but i could be wrong