[DanielDudley]

Originally Posted by fintstone

On an automotive gas gauge, a 12v 1N4742A 1W zener diode seems more likely. What did the gauge come off of?
https://www.ebay.com/itm/New-10-Pcs-x-1N4742A-1N4742-ZENER-DIODE-1W-12V-SALE/151138408274?_trkparms=aid%3D222007%26algo%3DSIM.M BE%26ao%3D1%26asc%3D20160908110712%26meid%3D353d02 363be44fca8e5eee5a6fb0f8eb%26pid%3D100677%26rk%3D3 %26rkt%3D30%26sd%3D221743500814&_trksid=p2385738.c100677.m4598

That looks a lot more like it Fint, but the numbers clearly read 40 04.

It's a Veglia Borletti gauge out of an 81 fuel injected Fiat Spider 2000.

Edit; Ordered a few anyway.