Merge Block issues (IsConnected)

I'm making a thing that moves along a rail and extends it as it goes, for various applications.

Basically, the thing moves along the rail with 2 merge blocks, but i'm having some issues.

The (MergeBlock).IsConnected function returns true as early as the merge block indicator turns yellow, eg. when it's getting close, but still isn't connected, does anyone know of a method of detecting if the merge block is actually merged? currently just checking the position of the piston moving the...

Merge Block issues (IsConnected)