My tripometer either records nothing, or, after some jiggling, it seems to work just fine.  And, no, the thread title is not incorrect.  I have had this problem with two tripometers.  One (the most recent), is in my original speedometer that had just been fully reconditioned.  After having it re-installed in the car, where it worked for the shop installing it, after I reset it to zero, it did not register any miles.  As I continued to drive, I jiggled it, and it started to record miles.  This leads me to beleive that it is a problem with the reset cable, not the tripometer itself.

Replace or rebuild the cable. They have a tendency to stick, and not release fully after re-setting the mileage. Sometimes if you pull down on it, it helps, but the real solution is to either replace it, or tear it apart, clean, and relube. There is a tool available to "fix" the cable, and the button/knob on the end. I'll have to dig and find out who has it, tho, unless someone else knows.

My tripometer works just fine!!!!  No problems so far, I just turned 130,000 miles !!

Sell it before you burn through all that bonus money!

Oh, it's gone...  Final update to come soon, hopefully