Electronic Speedometer
 

94 S350 D
Where is the sensor located for the speedometer?

The W140 chassis uses a processed signal fron the ABS computer to the inst cluster for the speedo.

OK so where is the ABS computer located?

Were you ever able to find out how to repair the speedometer in a 1994 S350D? If so could you guys post it for me?

The sensor (drivers side front) for the speedometer provides a signal to the ABS processor. The output is a square wave. You have to remember it goes thru a lot of wiring and connectors. I guess a test would be if the automatic conrol on the radio works, that would indicate there is a signal from it. MB gives values that can be measured on a volt meter or scope as the wheel is rotated. It also cold be a bad speedo since it is nothing but a meter getting voltage. The abs module is in the box at the base of the windshield in the engine compartment.