Problem with indexer limit switches

I am setting up our DX32 Explorer with an Allen Air pneumatic indexer plugged into the index connector. As long as a pause is programmed after each index step it seems to work OK except for one problem.

The "index back" switch (pins A, F on indexer connector) has no effect. The indexer will cycle from step to step with each M51 with the switch disconnected. There is a constant 10 VDC across the switch terminals.

From the Bridgeport schematic that came with the machine JP9-2A is to the index out switch, JP9-3A common, and JP9-2B is index back. I have assumed "out" and "back" correspond to the Allen Air piston positions, and both switches are connected normally open as shown in the diagram. Right?

I am going to run the machine as is but it would be nice if operation was suspended if the indexer failed to cycle through the entire distance.

Thanks for your help.

Johnhb