#1 My guess would be the blower motor regulator is shot. It is in the engine firewall area and not easy to get at.
#2 You will have to pull the strip and replace the bulb. Not sure how to do it on your car but BE CAREFUL as it will probably break.
#3 probably has dirty contacts somewhere in the seat area. The car is 25 years old.
#4 There are charts that give you the code messages. I don't have them.
Track down Jim Forgiones website. He has instructions for building a simple code reader. Sounds like you need one. And maybe a subscription to AllData for your car.
Anziani
'97 CL600 55K