I may try using your guidance in the DIY article to diagnosing my situation. The SRS light on my '88 300E has never worked since I purchase the car. My hope is that the bulb is simply burned out. All the other indicator lights come on as designed. If the default in the SRS system is for the light to come on, no light might just be a bad bulb. At least I hope so.
By the way is the SRS bulb used the same as other indicator lights (000 545 34 19)?