Upstairs AC zone not working

I just moved into a new house in November. It has central AC/Forced hot air and 2 zones. The zones split in the basement and are controlled via dampers from the main blower. In the winter, the heating system worked fine.

The previous owners disconnected power from the 1st floor damper and the linkage was broken that goes from the motor to the damper. After gluing the the linkage together so that it would open/close and applying power...zoning for the heat system worked properly.

Now it's time to turn on the AC and only the first floor t-stat will turn the AC system on. I switch both t-stats over to cool (new Honeywell programmable units), set them to call for AC...and only the first floor works. It works well when it's on.

From what I can tell, in "cool" mode, there is nothing telling the 2nd floor damper motor to open. If I manually rotate the linkage, the motor closes it again. Nothing I do allows the the upstairs t-stat to control the damper or AC unit when it's in cool mode.

Now, I only have 3 wires on the upstairs t-stat (R/W/G) and downstairs there are more (I forget all the colors.) Is this why my upstairs zone is not working? Is there a wiring scheme that doesn't have AC wiring going to the second zone?

In a pinch, I guess I could remove power from the upstairs damper motor, manually open it, and just have it cool the entire house. But that defeats the purpose of zones!! Help!

Thanks

The cold air will flow down through any other vents and stairwell. The upstairs takes priority when AC is needed. Perhaps the AC wasn't wired in to the downstairs stat?

The AC is wired into the downstairs t-stat and not the upstairs....or so it seems. The upstairs t-stat does nothing when trying to call for AC.

Also, the downstairs t-stat seems to be the "main" controller. If that is off...I can't use the upstairs t-stat to turn on the fan manually. If I set downstairs to cool or heat, I can manually turn the blower on using the upstairs t-stat.

You likely don't have enough wires for the t-stat upstairs and someone decided not to rip into the walls to install the correct wire.

So are you saying that KNOW there should be additional wires at the other tstat? The system is original to the house so I am not so sure that is the case

I was just thinking someone could have changed them. I would open them up and look for loose connections anyway while you check for how many wire to each. I just start at the dumb place and go from there.

I guess. I don't really think so though. I have the controller on page 16 and everything looks like it's wired correctly, maybe I have a bad relay? https://customer.honeywell.com/resources/techlit/TechLitDocuments/68-0000s/68-0101.pdf

All that is to deep for me, there is a reason I check the dumb stuff first.
Someone with real knowledge should be along soon to help you out.

Page 30, Step 6 in the right column:
1.) 0V on M1 to T5
2.) Disconnected T4,5,&6. Jumped T4 to T5 - does not open damper or turn on system
3.) All M1 to M4 and M1 to M6 readings correspond to whether the damper is open or closed.