Oil service light and broken odometers

[Boris3]

So I expect there is an easy answer to this.  My odometer doesn't work on the e30 318is, even with new gears installed so my thought has been that the motor that drives the gears may be fried. But, my oil service indicator lights do work (the staged countdown from multiple green to yellow to red) which are supposed to be based in part on mileage. Does the ECU record miles traveled and send info to the SI board? Is this another indication that the odometer motor is in fact fried since the diff rotation input is being sent/received elsewhere?

[B C]

The motor can be bad yes. The odometer gear sellers also indicate that not cleaning any dust or gear fragments very thoroughly can stop the motor. Seems strange, but I have experienced a repaired cluster working 1 out of every 100 miles or so.

The ecu does not have any mileage log like a newer BMW does. My belief of how the SI lights work is based on injection pulses/rpm like how the economy gauge works. In that way it can determine how many revolutions/the relative engine load to make a more adaptive service interval

[Jdesign]

New SI board batteries too?