MB Quart black box remotes WRC-S2

[lsvboombox]

Would anyone happen two know how many wired remotes the MB Quart black box will support? I have a 2010 Outback V which came with the black box main unit which is connected to a main controller which is in the glove box, it also has a WRC-S2 wired remote at the drivers console. I bought the (Y) splitter cable and another WRC-S2 remote for the transom. It was working just fine for about a week and now all three displays are blank. When I unplug the new remote the other two work just fine. Just wondering is anyone else has run into this issue.

i have 3 on my boat.. 1 direct and the other 2 have a y harness

2 are wrc-p
1 wrc-s2