my 1993 ford explorer manual trans 4wd stays on?

Any chance the wiring harness has come disconnected underneath the vehicle ? Look to see if the wires on the transfer case under the auto (crawl under drivers door area and you will see it) have come loose or broken with age. Don't forget to run the codes to see what it reads (the 4x4 operations motor could be bad) and if nothing comes up check the dash switch as well. Some auto parts stores will run the codes for free.

The 4wd light won't throw a code, but when had the same problem with my 93 eddie bauer it was the switch $ 300 at the dealership

DANG! $300? $40 switch, $50 r&r labor and the rest diags I'll bet. It's possible that you have the same or very similar concern. There should be a 2-wire switch on top or near the top of the transfer case that turns on the 4x4 light. I have an F-250 in our fleet that has gone through 3 of them this year.