Can't say I invested much time in ensuring this is the best one, but here is a video of some of the lamps.
Judging by the one on the left, nothing is going on during attract mode.
EDIT: There is a little bit, but only during a specific part: see avi file here:
http://arcadius.esero.net/Arcade/Cabinets/MIDWAY_OffRoad_Thunder_A/First coin in - tach and speedo light up
Total amount to play entered - delay, then start button lights up when start screen appears
View buttons - active view button is illuminated
Nitro - The only lamp I see in the instructions is the one inside the nitro button. Not exactly sure how it behaves. I would guess it's illuminated when you have nitro available and goes out when you run out. A video of hydro thunder had it flashing rapidly before the race starts.
Race Leader Upper/lower - would be self explanatory if not for the separate upper and lower. I am not seeing anything in the manual about a Race Leader panel. I also don't see it in any pics.
Honestly I'm not all that worried about making things blink properly.
EDIT: OK, the Race Leader light was located in a topper used on linked setups. The offroad Thunder one was rare and I could only find a picture of a thumbnail of it.
Hydro thunder also attached so you get the idea. Upper/Lower could be the part that says Race Leader and then the number. Number being illuminated if participating...maybe.
I will look for a manual for the topper.
IIRC, the movie theater I'm going to this weekend (to see Deadpool) has some game with that blue hydro thunder seat.
I think it's hydro thunder, but not 100% sure. If it is, I'll get video of the behavior of the lights. It was Rush 2049. If need be, I will go back and record some video when and if you take on that one.