The fridge side started warming up, while the freezer remained fine. Very little cold air coming through the upper port in the fridge with the setting at MAX and the port that goes into the meat/cheese drawer. Bad ADC board, right?

1. I took off the back panels in the freezer. There was no frost buildup on the coils and no extra ice around the drain hole. I replaced the ADC board two years ago, so I know what that kind of frost buildup looks like.

2. The evaporator fan spins fine (I observed it running).

3. I checked the air flow coming out of the upper damper with the freezer door open and closed. The output was the same.

4. Compressor fan running fine.

5. The unit doesn't run continuously (like it did with a bad ADC board).

6. I cleaned what I could get at from the back side of the unit. No change.

7. The interior lights go out when the door switch is pressed.

8. There is good air flow in the port where the freezer pulls air from the fridge. The flap is drawn in toward the freezer like it should

So, I think I ruled out a bad ADC board, bad evaporator fan, and bad defrost heater.

There are two anomalies:

A. The strip on the very front between the freezer and fridge compartments is warm to the touch. I don't know what could be hot there.

B. There was a very small bit of ice around the port in the fridge that feeds from the freezer into the meat/cheese drawer. I cleaned it off and poked my finger into the hole. Couldn't feel any further ice.

I'm stumped. Any ideas out there?

I did a quick check of the parts list for my model. A thermistor isn't listed as one of the parts.

Here are your parts includes a wiring diagram.
Parts for Maytag MSD2756GES Refrigerator - AppliancePartsPros.com

[COLOR="Blue"]2. The evaporator fan spins fine (I observed it running).[/COLOR]
Is it pushing lots of air?

[COLOR="Blue"]3. I checked the air flow coming out of the upper damper with the freezer door open and closed. The output was the same.[/COLOR]
Something is wrong here.
You should get more air flow into the fresh food side with it open.
Freezer door must be shut.
[COLOR="Blue"]
6. I cleaned what I could get at from the back side of the unit. No change.[/COLOR]
Looks like the unit uses a jelly roll condenser. They are a pain to clean.
If they look fairly dust free they should be OK.
A small mirror and a flashlight should help you check them.
I do not think this is part of your current problem.
The only way I have found to clean them properly is to blow them clean with compressed air but dust gets everywhere.

[COLOR="Blue"]So, I think I ruled out a bad ADC board, bad evaporator fan, and bad defrost heater[/COLOR]
I agree with you

There are two anomalies:

[COLOR="Blue"]A. The strip on the very front between the freezer and fridge compartments is warm to the touch. I don't know what could be hot there.[/COLOR]
Just warm is OK.
This will prevent condensation.
If it gets too warm/hot it is an indication that there is a problem removing the heat from the condenser coils.
This could be a bad condenser/compressor fan, dirty condenser coils or the fan blade or dirty vents on the rear cover plate or kick plate.

[COLOR="Blue"]B. There was a very small bit of ice around the port in the fridge that feeds from the freezer into the meat/cheese drawer. I cleaned it off and poked my finger into the hole. Couldn't feel any further ice.[/COLOR]
You have to make sure that the vent between the two compartments on the side wall is clear on both sides.

The unit does not use a thermistor.
It uses a thermostat (Item 3 in section 02) for the main temperature control.
Also has a thermostat(item 8 in section 02) for the damper door control.

Note that if you click on a part's description/picture a new page will open with additional info on that part, often there is a Q&A section which may help you.

Sounds like the damper flap is not opening re: no change in air flow.

I am not sure what is going on here as everything you list looks OK except the air flow into the fresh food side but you said that the flap was opening so I am a bit lost.
It would not hurt to check the freezer temperature. It should be between 0 and 5 degrees F.

Perhaps the following manual will help you.
You will have to join the site and be logged in to be able to download it.
http://appliancejunk.com...e&id=40;t=1406885225

New problem. I took the damper assembly off to check if there was anything blocking the damper door. In doing so, I unplugged the fridge and disconnected the wiring harnesses near the damper assembly to free it up. When I plugged everything back together, the motor fan would spin a couple of times, then stop. I took the damper assembly off again to check my connections and everything was fine. But again the motor fan would spin a few times, then stop.

Next, I had a service guy come out. After metering a few spots in the back and around the damper assembly, he said I probably had a dead short somewhere in the back of the unit that he couldn't get at and that I need a new fridge.

After he left, I left the power plugged in. I ran some errands for less than two hours, came back, and the unit was running.

My question: Is there some kind of reset mechanism in these units that would account for this behavior or could there be a short (that isn't shorting at the moment)? It's been running for two days now albeit with the same problem as originated this thread.