87 Eldo problem

Hello,
I'm new to this forum and could use some help please. My 87 Eldo started and was running fine but when I put it into gear (auto on console)it stalled and will not start now. I've lost all my instrumentation and the radiator fan comes on while cold. Ive checked all fuses and even swapped out ECM's without any luck. Cannot even check for codes using the self diagnostics since I have no display whatsoever. Engine turns over but the injectors are not firing. Plenty of spark at the plugs though. This is very strange since car was running fine and now dealer only wants me to bring it in(of course,$$$$$). Has anyone come across this problem? Any and all help is greatly appreciated! TIA to All who reply.