Problem spindle indexing

so here is my situation...

i recently aquired a wasino lg-81 gang style lathe, which is great, and it has the capability to index the spindle and a live tool, only i cant figure it out...

i have only run it in mdi like this ...

m52
s1800
(go)

which should, as far as i can tell, index the spindle to 180deg with no problem,

and the spindle turns to 180deg and locks, which all seems right. Exept the error light lights up and i have to reset, and unlock, before i can do anything else

any insight would be appreciated