Odometer out

I recently bought a 97 XJ that had/has a few minor problems that will be taken care of over the next few months. One that has baffled me is the odometer not being lit. It's a 97, 4.0, AW4, 231. I have done some searching but all I seem to find about odometers is when people are trying to roll them back

Other problems that are electrical related have either been resolved or are absolutely irrelevant: left side running lights out (fuse and bad grounds), LF speaker not working (shouldn't be hard to figure out and shouldn't be related) and cruise not working (fuse and bad grounds).

I can still use the overhead console's odometer for my oil change intervals so it's not absolutely necessary, but I'd like it to work again. Kinda hoping I don't need to put in another cluster. Not that it would be difficult, I would just rather keep the correct miles for my own personal satisfaction.

Any ideas? I wouldn't bet on a bulb, aren't those displays LCD?

No bulb, they are self luminating. I assume the rest of the cluster works? The PCM communicates with the cluster and the electronics in it figures out what to display. The odometer is non-volatile RAM. Sort of sounds like the driver electronics for the display has taken a vacation to the Bahamas. If so, a replacement cluster will be needed.

It's a "vacuum fluorescent digital display tube" according to the manual.

Have you run the cluster self test yet? That won't accomplish much, but should at least tell you whether the problem is the display itself, or lies elsewhere.

Yes, the rest of the cluster works. All gauges and lights function. I was unaware of a cluster self test. It sounds as if it will indeed take a cluster. Does the PCM tell the display what to read as far as the number of miles? So if I put another cluster in, it would read my PCM's mileage?

It's more than 10 years old so mileage on the title is exempt. BMV doesn't care. Those nazis can sit on it anyhow.

Test is pretty handy. Press the trip reset button and hold it, then turn the key to on (don't crank it over though). Let go of the button, and the cluster will go through a little routine. The odometer will start showing all 0s, then all 1s, 2s, counting up to 9 while the gauges step from low to high, all the warnings light up, etc. I'm guessing yours won't show anything on the odometer, which would indicate a problem with the display, since it's communicating with the PCM at that point, IINM.

The PCM tells the odometer to keep adding, but AFAIK the mileages are stored in the cluster, so if you replace it with another XJ or TJ cluster, you'll show whatever miles the other Jeep had.