Does the 3-wire cable on the right really go to a light, or to the other switch?

actually, not sure, never looked. I'm at work now, otherwise i would check and give you an answer.

BUT - i'm assuming the switch. There's a 3-way wire and a 2-way wire going from the light to upstairs (top of the stairway).

The stuff I've found online shows two 2-way running to the other side, not a 3-way and 2-way.

Hello ericksobj

Do the Upstairs and Downstairs lights both
go on and off with the same 3 way switch??

Have A Nice Day
Linesman

Linesman - I'd assume that both lights are controlled by both switches, otherwise 3-wire cables to the switches would not be needed.
Erick - try this:
Number the wires on your drawing 1-12, starting with the black power wire (#1) and going clockwise, so that the red wire on the left is #12.
I am also assuming that the 3-wire cable on the right on your drawing, labeled "Goes Up Stair to Light" actually goes to the other 3-way switch.
Connect as follows:
Connect wires 1 & 10.
Re-identify both ends of wire 10 as hot (with black tape or a marker) if they are not already. At the switch, wire 10 connects to the Common terminal. The remaining wires (11 & 12) can go on either of the remaining switch terminals.
Connect wires 3 & 12 (Traveler)
Connect wires 4 & 11 (Traveler)
Connect wires 5, 6, and 9. Re-identify both ends of wire 5 as hot. At the switch, wire 5 connects to the Common terminal. The remaining wires (3 & 4) can go on either of the remaining switch terminals.
Connect wires 2, 7 and 8. (These are neutrals - no need to re-identify)

thanks hrajotte.

i'll try it.

my only concern is that i haven't touched the light and switch at the top of the stairs, so re-wiring those would be a change.

If that's what i have to do, then fine. but it's not the same as what it was before.

THANKS!

Hello ericksobj

Here is a drawing that I made, connecting the wires that you had in your drawing..I think this is your trying to do.

Hope This Helps....

The drawing is almost like the way hrajotte has written it out

Have A Nice Day
Linesman

PERFECT!!

Thanks