Any gauge shop should be able to fix it but before you do that, call Wilkinson to see what a new one costs. It might be cheaper to buy a new one. The OEM gauges are not expensive.
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.