97 Towncar overdrive

The first tme I pushed the OD button on the end of the shift lever with car running and not in gear or moving the engine stopped running and the fuse burnt, a new fuse was installed and car started as usual. I hope someone can tell me now the OD works, does the car have to be at a cetain speed. etc, I do not have any material on how the OD operates, or is there something wrong with the OD system.

Definately a big problem is that "first" behavior persists.

You can push that button anytime you please. OD is the default operating position, and pressing the button disables the OD. When disabled, there's a lighted message on the speedo saying "Overdrive Off" or something to that effect. If there's no "OFF" message, the OD is "ON", allowing the trannie to shift to a "4th" gear.

I can look up the specifics if you like, but I've hit the OD "OFF" button running 70/75 mph and it simply downshifts to 3rd gear.