[Jawkn333]

My dash has the climate control where temperature is set. Not sure what type that is considered. All buttons and lights work. Air blows strong, it just isn't warm. I do not think the thermostat is the issue, because the engine temp gauge is cold when started and reaches the normal point.
I serviced the cooling system to remove any possible air pockets. After manually squeezing the two (3?) firewall coolant inlet hoses for several minutes while running with air on, it did warm up slightly. Although, it is winter and I don't feel the coolant cycling. One firewall hose is hot while the other is warm. Does the heater core have a separate pump. I do lose a small amount of coolant and need topped off every 3 months or so, especially in the summer.
Question is heater core or water pump? It does NOT drip like a car i had in the past where pump was bad. I have not done voltage tests on heater core, unsure of which fuse it even is.
Car has 250k+ miles and unsure of water pump/core services previous to my ownership. Some direction on diagnosis is needed thank you.

 

[Drunken Elvis]

The return hose from the heater core is noticeably cooler than the inlet hose. This means the fluid is losing what heat it can while inside the car and yet you still don't have good heat. Logic would then say there is in inadequate flow of coolant. The engine operates fine and does not overheat, indicating the water pump is functioning properly. Only thing left is a partially obstructed heater core. Remove the hoses [loss of coolant will happen] and back flush the heater core.
I've been wrong before.

 

[DrivenDaily]

The HVAC (heat, ventilation, air conditioning) controls with a temperature setting are called Automatic Climate Control. The ones without are called Manual Climate Control.

The heater core does not have a separate pump. Good question, though. The engine's water pump is the only water pump you have.

I tend to agree with @Drunken Elvis regarding some kind of stoppage in the heater core.

Next question is when was the last time the coolant was ever flushed? If it has been a long time, you might consider setting a time to do it. For me, whenever I flush mine, I replace the water pump, thermostat, and as many hoses as I can. I also flush both the heater core and the radiator.

I have had 2 bad experiences where I didn't replace the pump, and both times I was hours away from home with family in the car. On my 2 current vehicles, I've had cooling issues and elected to replace what I mention above. One of those is a 2011 3.6L LTZ with the same temperature controls as yours.

Another possibility, although remote, is that the temperature door is somehow obstructed, but the better chance is the heater core is clogged.

Also, when adding coolant, you MUST use the same type as what is in the system. Mixing coolant that either is, or is compatible with, DexCool and coolant that is not compatible will result in a thick goo forming. The first places to clog up are the narrow passages in the heater core and radiator. If that has happened, you should flush the entire system and top off with DexCool (or compatible) coolant. And my recommendation would be to change the water pump, t-stat, and all hoses, but that's up to you.

 

[Jawkn333]

Thank you for the prompt helpful replies!
That is a good point about mixing coolant types i was not aware. Since its been topped off so many times, a flush would be a good idea I think for sure. I would also like to do the water pump for good measure, so this might be a sign that it is time. I alreary have a brand new belt tensioner to boot as well

 

[jay gaver]

My dash has the climate control where temperature is set. Not sure what type that is considered. All buttons and lights work. Air blows strong, it just isn't warm. I do not think the thermostat is the issue, because the engine temp gauge is cold when started and reaches the normal point.
I serviced the cooling system to remove any possible air pockets. After manually squeezing the two (3?) firewall coolant inlet hoses for several minutes while running with air on, it did warm up slightly. Although, it is winter and I don't feel the coolant cycling. One firewall hose is hot while the other is warm. Does the heater core have a separate pump. I do lose a small amount of coolant and need topped off every 3 months or so, especially in the summer.
Question is heater core or water pump? It does NOT drip like a car i had in the past where pump was bad. I have not done voltage tests on heater core, unsure of which fuse it even is.
Car has 250k+ miles and unsure of water pump/core services previous to my ownership. Some direction on diagnosis is needed thank you.

Water pumps on these gen 7 cars are prone to leak. Check below the pump for leaks. At 250k pretty much everything should be considered for replacement. Car might not be worth the repair costs unless you do it yourself, which is not that diffiult. Youtube!!!

 

[Jawkn333]

I've had odd electrical issues with this car recently. I left the battery disconnected overnight, and voila! Heat again. I know moisture is building up inside the cabin and frosting the inside of my windshield. Door seals maybe I will need to investigate when its warmer outside.
Anyway, my interior fuse box's fuses are not blown, but have copper buildup film. I've had to scrape a fuse clean to get it to work again.
Thanks all!