Distance to empty display is stuck on 24

[jeffro]

1989 325i convertible, auto trans

My distance to empty display always says 24 miles to empty no matter how much gas is in the tank. All the other gauges and info displays work fine. I would think the DTE would use the gas gauge. The gas gauge works though. There must be another electrical path that the DTE uses to calculate its display. Any ideas on where to look to fix this?

Thanks,
J-