@gto49
Ok, a few hours later, and still no help. I've been checking Kasa/TP-Link customer support and have created a case number and the response I received says I would hear from them within 48 hours, but if urgent (its not) I can do the chat thing.
What I have discovered from the Support pages is there are two versions of this 3-way dimmer KS230: V1 and V2. When I select V2 (which I have), there are only two hardware versions I can choose from: V1 or V1.8. I have V2.20. I have no idea what the differences are. In fact, when I ordered the KS230 kit, I was not aware there were two different versions. In checking the instalation instructions for V1 (or V1.8?), I see there is a difference in the connections. In the other version (V1), there is no Load wire coming out of the Sat switch, and you must differentiate between the two travelers, labelling them T1 and T2. The Load wire in the Sat box is connected to the T2 traveler terminal along with the T2 wire. Again, there is no Load wire coming out of the Sat switch at all. Both the Load wire and the T2 wire are connected to the same Traveler terminal on the Sat switch. That's quite different than the V2 version I have.
I don't know if the V1 kit can fix my issue. I only say that because no matter how I connect the Main dimmer switch in the V2.20 version I have, when I turn on the breaker and check the active wires with my tester, there is no power going to the Sat box in the basement. Nothing. There is power in the Line wire in the Main box, and power in the white Neutral wire coming out of the switch, but absolutely nothing in either of the travelers -- and from what I can determine from the old setup with the dumb switches, whether the lights are on or off, one of the travelers is active. Same with the Sat box in the basement. With the old dumb setup, no matter if the lights are on or off, there is power to something in the Sat box. But not with the smart dimmers. I get nothing. The Main dimmer has no lights at all. Holding the left reset button down on the switch does not do anything.
I've tried everything at least a half-dozen times, and nothing changes. No power goes to the Sat box downstairs, and no lights appear on the Main switch. That being the case, no matter how the Sat switch is wired up, since there is no power going to it from the Main switch, I assume nothing will change. I was tempted to connect the Load wire in the Sat box to the T2 terminal along with the T2 wire on the Sat switch, but I don't see how that will change anything when there's no power going to any of the wires in the Sat box in the first place.
So I'm at a dead end. This was supposed to be easy, just for the convenience of controlling my basement lights using my phone. I believe the only option I have, if I want dimmer switches, is to buy dumb dimmers. But at least then I can dim the lights. 150W of LED lighting is nice and bright but I don't need 100% brightness all the time.
I'll wait until after the weekend. Hopefully someone can help me figure this out. 🤷♂️ Nothing like a pair of smart switches to make you feel like a dummy.