WHAT IS THE CORRECT WAY TO WIRE A WYE LIONEL SWITCH USING TMCC? iF WIRED USING THE POINTS ON REVERSE SIDE THE SWITCH WILL NOT OPEN OR CLOSE.
First, welcome to the forum. Second, you should probably post this question on the Classic Toy Trains category. I think you’ll get more Lionel users there.
Are you asking about 3-rail Lionel O or O27? Can you post a picture of the switch?
I’m thinking the only Wye Lionel has recently made is within the FasTrack system.
There were 2 versions, I believe, one with only a standard control switch (but could be wired for TMCC using an SC-2 or ASC controller), and one that had TMCC control included within the Wye itself (only needs the command base, no SC-2 or ASC required).
Original: FasTrack O72 WYE Remote Switch
TMCC included: FasTrack O72 Remote/Command Control Wye Switch
(to add to the confusion, Lionel’s web page for the command controlled switch refers to the SC2 and ASC box hook ups, which would not normally be required. Probably someone did a cut and paste when making the web page 
)
More detail will be needed as to what is currently hooked up and which Wye is being used. If it’s the second one, no hookup should be required aside from the command base to the outside rail as with everything else TMCC. If it’s the 1st, we need to know EXACTLY what is hooked up and how.
And of course, even if everything is hooked up properly, the unit needs to be programmed properly in order to respond to the TMCC commands. Just like anything else TMCC, it needs to be addressed with the correct number to respond.
(in all cases above, even though I said “TMCC”, Legacy can also be used. The process should be no different)
I’d say a good first step of trouble shooting might be to hook up the switch using the lever control box (if that is the version you have) and make sure the switch works conventionally.
This can be checked with the wye not installed on the layout. Just apply power to center and outside rails temporarily with alligator clip leads and make sure the controller toggles the wye position. If it doesn’t, it’s possible something within the switch motor control itself may be faulty. If that is the case, then it won’t work under TMCC control either.