If the compass still works, then either the DIC controller failed, or the screen failed on the DIC module. Does the DIC still beep at you when a door is open or you're low on fuel? Obviously you can't see what it'* complaining about, but you know that be-be-be-beep.
You said you replaced the DIC with a used one. Do you mean the module [Screen, thing you see on IP] or the controller? And was the unit you replaced it with working in the donor car? You gotta remember like 80% of DIC/Compasses don't work in our SSEs. However the common problem when BOTH compass and DIC don't work is in the compass module, which is the most common problem with the clusters. However I believe the second problem is screen failure, which I believe is what is wrong with my 2nd cluster.
'89 SSE - GX3 -190k, 155k on body - Back for another ride.