Here's what I know so far,
The monovalve is ok, the aux water pump is ok, heater core is not clogged, the temp sensor vent by the sun visors is working.
Normally I get a little heat in the car but not enough to really be warm, I have been trying to figure this out for a month.

Last wed I was driving down the interstate and the windshield began to fog. I pushed the defrost button and I got some serious heat coming out the defrost vents. I tried the other buttons and got really good heat on each one. I also had heat coming out the middle dash vents,, a first. I also could hear a new "door opening sound" under the dash. The amount of heat I got seemed to change each time I heard this door open or close. It also seemed to be too drastic of a change for it to be normal. I've driven the car 2 or 3 times since then and I don't get much heat and I don't hear that door.

How can I begin to troubleshoot this?
Thanks!
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