Thanks gang, I will check for shorts as that seems like the problem I need to tackle first. This has been really frustrating as the car shifted buttery smooth, then all of a sudden it stopped upshifting.

I tend to agree than the Shifter is likely at fault. (but I will work through each fault before I start buying parts).

BTW, I have been told it is impossible to use a Used Shifter as they must be programmed to work with each car. This doesn't sound right, but I don't work with electronics much.

Any truth to that? It will increase the cost significantly if it's a New Only, Dealer Only part.

Thanks,
Larry