BMW E30 service light rest
The old style (pre-88) E30s have the rounded connectors, the newer ones have the other style, properly circular.
To sum up, you need to short pins 7 and 19. Then switch the ignition to the point where the gauges come on and you can use the blower motors. Watch the service indicators and when they reset, turn off the ignition and remove the short.
It's just your car's built in trip computer telling you it's approaching 6,000 miles or whatever since its last reset.