SLK SRS light comes on after 5 minutes. Help!

[sdhester]

2001 SLK 230 SRS light comes on after 5 minutes and stays on. No leak or water issues. The 5 minutes is consistent - it applies whether the car is traveling, parked and running, or simply off but the ignition on. I have owned the car since new. Never before saw the issue. I had just replaced a fuse (F7 - roof switch), and taken the battery lead off for 24 hours. There was not other disturbance to the car.