[Towncar]

Welcome to AF Lincolns!!

I wouldn't be too quick to blame the computer.

What, if anything happened to the car between the last time it worked properly and now?

I'd suspect a "fusible link", power relay, or master fuse in this case. There's at least two fusible llinks wrapped tight inside the wiring harness coming from the battery. The power relays are inside the main power distribution box under the hood, and possibly the master fuses are there too.

I don't have a 98 reference guide so I'm basically going with knowledge of the 96, hope that might lead you in the right direction.

PS:
When testing the fuse holder, you'll need a 12v test lamp to be sure there's power running through the fuse holder pins.