On my 92 grand marquis the digital speedometer numbers are not right. 4 look like a H, 2 not right and 5 are 6. What is wrong?

You likely need a new instrument panel cluster.

Hi I rebuild electronic speedometers. I haven't seen it on many Grand Marquis speedos but in many other digital fords the microprocessor or display driver is starting to fail. Doubt it is a power supply unless you have fading digits. Either case, TXGreaseMonkey was right, you need a new one or get yours rebuilt.