Questions?
What components in the speedometer are effected to cause it to just stop working? I know this is a dumb question, but, I want to understand a little better. I was entering the highway the other morning and when I reached to set the cruise control, the speedometer read "zero". It was working perfectly before. I did not hear any noise or notice anything unusual. Has anybody in this forum ever had this to happen? Am I really about to hit my hip pocket? Could the cruise control cause this problem? I use and admire the different points of view that I get when I use this forum. Thanks!

Were your other dash guages working? If not it is most likely a fuse. I had the same problem. Started up the car and none of the dash guages worked. Got a spare fuse from the glove box and it was fixed. If everything else is working it is possbile there is a loose connection at the back of the guage cluster, or it could be one of a few other problems, none of which I really know anything about.

Speedometer not working - '86' 420SEL (Part 2)
 

I forgot to mention that all other gauges, clock, odometer, etc., are working fine. I changed every single fuse in the fuse box and made sure they were seated properly. I took the car for a drive and still nothing. Is there anything else I can do? Thanks!