Hi NY Guy,
I suppose once that is a PLC from GE, it works like an OMROM PLC.
I mean, you need a computer, software from GE and a RS422 Cable to connect to your PLC.
Then you can change all logical outputs including, that one you said it causing issues.
So I think there isn't any service tool or test tool for connect to GE'S PLC.
I hope have helped.
Cheers