10 diagnostic monitor internal thermal fuse - open due to intermittent short to ground 1991 town car?

This is an airbag fault code. The airbag system in this car has a fuse in the main module that will open after airbag deployment or in the event of a short (as in your case) or malfunction in the airbags or wiring to the airbags. You must find the cause of the short and correct it, then change the airbag module, as the fuse is not a replacable item. A common short point in this car is the airbag clock spring under the steering wheel. This part has a contact that moves when the steering wheel is turned. The contact provides an electrical connection to the drivers airbag. The clockspring will sometimes wear out and cause a direct short. This will take out the thermal fuse and disable the airbag system. You need to have some electrical troubleshooting experience and have a multimeter and a service manual to troubleshoot and repair this. If the clockspring needs to be replaced you have to pull the steering wheel and dissasemble the steeing coulm. If you are mechanically inclined then go for it, if not leave this job to someone else! Hope this helps JSS