Need help with dual gauge

[Ricosan]

I had my dual gauge from my "34 cabriolet rebuilt about 4 months ago. It was working at the time but the case on the back had completely deteriorated.

After receiving the rebuilt gauge I took it to my mechanic and he installed it. It didn't work.

I sent it back to the company that rebuilt it. They repaired it and returned it to me. My mechanic installed it and it didn't work.

I sent it back for a third time. They repaired it and sent it back. My mechanic installed it and it doesn't work!

I watched the mechanic install the gauge and I saw nothing that would (IMO) cause a failure.

After each installation was removed, I carefully examined the unit and couldn't find anything that looked wrong.

Can anyone shed some light on this?

ricosan