LS 185 b EIC board doesn't light up when getting into the seat. Start in service only and when switching back to normal operating position it shuts down. Suggestions
Put a jumperon the connection for the under the seat switch to check it. When you run it in service does the display work? On a older one I would suspect the starter interlock relay also.
If EIC doesn't light up but it starts in service position, seat switch is the place to start.