i've got a nice 240 DL that it's odometer stopped working. i've replaced the gears on these before so I figured I'd get in and out in an hour with it fixed. Well, not only does the odometer still not work ($50 gear) but now the speedometer spikes on me while driving (which did not happen prior to replacing the gear today). I'm not sure what went wrong but can anyone help me figure this one out? I've connected all the wires to the dash housing properly and all other dash functions work properly as well. Do I need to take it all apart again? thank you for you help everyone.

 

disconnect neg battery cable and take it out again....maybe some soldering needs to be done. I did 3 of the gear replacement and at least one time I missed a connection. Some guy had to re solder a spot (I can't remember of course right!) on the speedometer. My gear replacement diy project ended up going bad again after a month...!

 

Is your 90 an ABS equipped car? If so, the speedo internal motor bits are prone to failure. Still, since it worked prior to disassembly, it is probably best to tear into it again and double check all connections.