Mercedes,

The odometer number wheels sometimes slip on the metal shaft. Some epoxy or miracle glue will usually fix them. To remove the instrument cluster, work thin pieces of metal along side the cluster and work it out.

Take the brown vacuum line off at the opposite end of where it is connected to the IP. With the engine running, suck on the end of the vacuum line and notice if you can feel a vacuum. No vacuum, the diaphram is bad. If the shutoff solonoid is working correctly, sucking on it should off the engine. In that case the problem is the vacuum pump, key switch or vaacuum leak.

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