Tripmeter stopped working, W123

[H-townbenzoboy]

I'm accustomed to W123s and W126s having simultaneous odometer/tripometer failure, but not just tripometer failure. I filled up the tank earlier today, and reset my tripometer at (275.9), the car was off and sitting still when I reset it. Well, at approximately nine tenths of a mile into my trip home, the tripometer ceased to function. The odometer however, is still working. It read 347,179 at the truck stop, and 347,186 when I got home, which is correct. So, I think the old "roughen up the shaft" fix doesn't apply in this situation since we're dealing with the tripometer only. Someone, what do I need to look for? I'm going to have it out in a few days anyway to put a good instrument cluster housing in, gauges are loose because some of the screw holes are broken, light leaks through some of the gauge holes as a result at night, and I can't reset the trip or set the clock without the gauge itself being pushed in a bit. Maybe that has something to do with it?

-Joe

Have you taken it apart and looked inside the cluster yet? If the screw holes are broken, the odometer reset lever may be stuck in the reset position, which could keep the odometer disengaged. It sounds like you need to have a look inside and see if the problem is the speedometer unit itself or the plastic cluster.

[davidhoward]

My '81 300D has the same problem... When reset it goes to .9 then sticks, after a great while it may start working again until 1.9, then stick for a long while and proceed to 2.9. It never gets above that. When reset to 0, it starts the whole .9 stick routine again. Odometer work fine.

[H-townbenzoboy]

Originally Posted by Craig

Have you taken it apart and looked inside the cluster yet? If the screw holes are broken, the odometer reset lever may be stuck in the reset position, which could keep the odometer disengaged. It sounds like you need to have a look inside and see if the problem is the speedometer unit itself or the plastic cluster.

I took the underdash panel off, held the speedometer in from the back with one hand while I pressed the reset button with the other. It worked! Everything's a'ok now.
-Joe

Good news, are you still going to replace the plastic cluster? I have a spare cluster, but I think it has one broken screw hole.

[H-townbenzoboy]

I'm still going to replace the cluster housing, I paid for a good replacement one that's going to arrive later this week.
-Joe