The speedometer/odometer guage have stopped working on my 1992 325 ic. What could the problem be?

Sounds like the body control module has gone bad. It has a relay that caries considerable current to all of these accesories and wears out.
It can also be a solder joint on the circuit board where this relay mounts.
Hope this helps, Robert

try checking the fuses

sounds like the main fuse has blew which is under the hood

Hello Durham.
Couple of possible problems here.

Does the odometer work? If it does your speedometer is defective and will need replacement.

Or if your check engine light is on your speed sensor or wiring will likely be the issue. This will also affect the odometer.

i actually have this exact problem with my 92, to get the cluster set out is a pain in the ***, but i will try to explain..
first, there are 4-5 screws at the top of the fake wood trim above the guage set, remove them, then remove the top panel, then you'll find another 4-5 screws (top and bot sides) holding the lower piece on, remove them.
once you have the cluser set exposed, remove the 5-6 screws holding it in place, you'll be able to pull the set out, make sure to disconnect all the wires going to the cluseter set, once you have it out, you will need to disaemble it.
if its a needle guage set (like mine) you'll find that each instrument is a "pod" which can be removed, there are 3 - 4 torx screws holding them inplace, simply remove the screws, then pull (fairly hard) and the speedometer should pop out..

My gas guage, speed odometer and tempiture does not work
The speed odometre is reading 9999999 what should i do

Problem is in the guage cluster assy.The ODO is mechanical,serviced by replacing guage cluster.

first check all the fuses and if they are good it may just be a bad cluster and you may have to replace it

check the vehicle speed sensor located on the transmission housing.

check for a speed sensor problem