The odometer for 2000 s500 not working how can i fix it

I didn't see an s15 in that model year, in my database?
If the speedometer works but the tach doesn't, I think something is wrong with instrument cluster?
GM has had a problem with fuel gage sending units. The sending units are not hard wired to instrument cluster, they send signal to pcm, the pcm sends serial data to instrument cluster, telling the cluster the gage settings.
It may be possible to use different size resistors in place of the fuel level sending unit, to see if fuel gage reacts properly to different resistors, if the gage reacts properly, then I think the problem is the fuel gage sending unit.

The sending unit is bad. Some cars need the fuel pump replacd. May b easier to just record ur miles

Check fuel gauge sensor , Code on computer

That means that the computer is having trouble talking to the sensors.

sounds Like You HAve Ground Problem Clean the CABLE Goin to Your Battery And then Look On YouTube to See How They Do It Ok

check you speedo sencer maybe replace it this will fix your problem

there is a sender in the fule tank this may be faulty so its not sending the info to the tank gage find the whire from this sender on the fule tank and short it out to the car bodywork the tank should then read full up if the wireing is good, if there is still no reading its likley to be the gage not working, or a broken wire to the sender,,,if the sender is broken it canot be fixed so fit a new one but check how much fule is in the tank before you try to remove the old sender or it may spill out every were, if you fit a new selder only add a gall of fule and see if there is a reading on the gage before adding more so you find out when the tank is realy empty,, never trust the gage to be true

when you pulled the top of the dash off did you check the cable connection to the insturment cluster. i had a similar problem where my gauges died individually including the spedo and tach. slapping the dash usually would cause the gauges to start working again, but that quit also and i had to tear the cluster out and check the conneciton. that fixed the problem.

wont get one on till almost out of fuel just go by the fuel gage if that dosent work go by your trip odometer on your next fill up

You need to pull the dash and check the guages look for any burning or melting. You may just need to replace the pannel in your dash, pretty easy work. If not start checking the wires and cables that come out of your faulty guages.

tepfy