What year car?

Couple questions - do the odometer and/or trip meter work?

I have a 1987 740 - everything on the dash works except the speedo.
Here's the most common problem:
Jack up the rear of your car and look at the rear differential. There
will be 2 wires with a snap on connector. There is a magnet inside of
the diff that sends a signal through these wires to your speedo on the
dash. If everything on the dash is dead - tach, speedo, mileage,
chances are these wires have worn out, maybe shorting, etc. Often a
repair of these wires will get you back in business. Unsnap the
connectors and inspect. No need to take out the diff unit - VERY rare
to fail.

If everything on the dash is working BUT the speedo - that's another
issue. I just took apart my cluster and it was not fun - tons of
little screws and when I pulled the speedo apart - coils of wires
inside. From here you have two choices - replacement speedo from the
boneyard or ship it off and pay the $100 or so they want.

Option three is find someone with instructions on repair. All I could
find was for a 200 dash and the speedo is different I think.

jamie