The A/C in my 99 is confused. In the winter it blows cold on one side and hot on the other. It is in "Defrost" mode 24/7 regardless of the selection. You cannot get the fan to blow at the highest speed in any mode.
Over time, I have replace every component of the A/C system. I sent the Control Module off the be "refurbished" and all they did was replace the lights.. I haven't been able to find any NOS modules.
Are there any NOS modules to be found? If not where can I find a shop whose units work like new?

 

From your description, it may well be you have other issues appearing to be the control module. My '99 acted similar when I first got it, and it took me a while to figure it out. You don't say so, but it sounds like a dual control, not the manual, correct?
You note having changed many of the components, but have you confirmed some of the basics? Temperature inconsistencies can come from less than ideal refrigerant charge, so we need to make sure that's good. I agree with others that having it checked by a professional is the best path, but personally I find getting to a professional and waiting for results can kill more time than I'm willing to lose. A gage set is great, but even a WallyWorld recharge can that has a proper dial gage can tell us a lot. If you hook up to the low side with the engine off -- and having been off for a number of hours, such as overnight -- the low pressure side should read pretty much the same pressure as ambient temperature, 90PSI on a 90°F day and similar. If it reads 40PSI on a 85° day, you are short refrigerant. The compressor will come on, then may cycle off, repeating as the pressure goes up and comes down. Between too low and just right there are fill levels where only half the evaporator gets refrigerant, leading to one side cooling and the other side not.
Do you have appropriate manifold vacuum at the heater box control valve? A lack of manifold vacuum will prevent the control circuit from switching modes, resulting in air coming from all the vents, including the defroster vents. It also prevents the fresh/recirculate valve from engaging. Full blower speed requires the mode switching to center dash vents, and recirculate mode so that existing cabin air is moved instead of trying to add additional cabin air. If cycling through the modes on the control unit does not switch the air flow, a broken vacuum line is the most common cause.

 

Wow! 90% of what you said is way above my pay grade. I will share it with my A/C guy.

 

It's not, it just takes a minute. You have to separate the issues and solve them individually. There are rather a number of sub-systems involved between vacuum and electric actuators and a reliable vacuum source. If you would, report back with how it goes with your A/C guy. More information is always valuable.
Also, keep an eye on the parts for sale forum and your local Facebook marketplace for control modules. The part numbers are not all the same through the years, but I have not seen anything saying for sure that they won't interchange. Other than the dim display issue, I have not seen a significant number of control units failing, so a used one has a good chance of being good. Anticipate around $250 for personal party used, $450 from a used part retailer.

 

My unit did go bad. I sent to Mid-America Motorworks and they said the needed part was not available. MAMO took > a month to say they couldn't fix it. I sent to Automotive Circuit solutions and for $100 plus shipping they had it turned around in a day (USPS had it to them in < a week). I sent the unit back to Automotive Circuit Solutions (Oct 24, 2024) for a warranty fix as they missed fixing the other big issue - the temperature adjust **** no longer adjusts. The USPS tracking now shows it in Topeka, KS - for the sixth time. It has been bouncing between Topeka and Kansas City (KS) for weeks. Sigh - not on topic but had to vent somewhere.