Odometer not working
 

I have a 1988 300E. The odometer will function at times and then not function at others. As well, when there is cold weather, the odometer will not work. Following refueling and restting the trip button, the odometer stops working. Sometimes, I shut the engine off, put the vehicle in park, let it sit a while then restart it and drive. The odometer sometimes begins to function.
Do you have any suggestions why the odometer is not working?;)
Fully repaired now. The single most triumph was to remove the instrument cluster without removing the speedometer cable form the transmission. I made my own tools from two bicycle spokes to remove the cluster.
The odometer operates very well, thank you.

I have repaired a couple of mechanical odometers/speedometers, 1 on a 1975 450SE and 1 on an early 70's 230(?). If yours isn't electric, read on.
In both cases there was a broken or loose gear on a splined shaft that needs to be replaced or repaired with epoxy. Take your instrument cluster out, then remove the speedometer part, and you'll quickly see the problem. Test the fix by chucking your drill onto the cable end of the speedo head and running it in reverse. Should read about 40mph, if I recall, but it's been years since I did this.
Do a search too, as I know I've read some posts on this subject.