Thanks, Stretch.
Finally got the top off the tach amp plug and that's what it is.
It was really stuck---probably hadn't been unscrewed since birth.
The other ones I've seen are taller.
The other object has an 80amp fuse in it like the one in the glow
plug relay. It disappears under the fusebox.
On the OVP--I don't have ABS. Just can't find any info online on
what that relay controls besides the tach on this year car.
Can't find anything in my FSM but it is missing some pages in the back.
There's always one mystery left to solve.
Jeff