Re: 84 733i speedometer woes

carl mciver wrote:

Will the batteries being dead have an effect on the speedometer?

I think they can. Bad SI (Service Indicator) batteries screw up a
bunch of stuff in there. As well, I understand that driving won't
recharge them by itself. You need to charge them before use. This is
why a lot of people swapping in replacements mount them remotely and
accessibly.

If the sender _and_ cluster is good, what else could be at fault here?

Well, I'm not sure you've determined the sender is good. Then, there's
all that wiring in there. Check for continuity from the sender
connector to the other end of the wires at the speedo head. If there's
a break, look under the car for brittle or burnt (exhaust leaks will
cook 'em) places where the wire might be broken. If you have
continuity, try replacing the sender in the diff. It's easy and
relatively cheap. If that fails, you're down to the cluster ...
--
C.R. Krieger

.