92 Buick odometer question

I picked up a 1992 Buick Regal Custom from my brother for my run around car. I noticed that the mileage odometer doesn't work. I'd like to figure what I'm getting for gas mileage. How hard is it to replace this cable. It has a 3.1 motor. Thanks, The Woodelf

If the speedometer doesn't work either, the problem may be the VSS. It is located on the upper rear of the differential housing on the transmission. It signals the ECM, which conditions (scales) the signal for the instrument cluster.

If the speedometer works but not the odometer, the problem is likely mechanical within the instrument cluster. The mechanism which drives the odometer is driven by the speedo. The trip odometer reset mechanism can affect the odometer as well.

I've had 2 of these clusters and its the worm gears inside that crumble. I used to use the tripometer thing a lot for checking mileage now i leave it alone. "Don't mess with success". I bought mine on eBay for $50.
I posted a section way back on how to remove dash etc., pretty easy actually.

Good luck