Hummer H3 oil pressure sensor replacing, location, easy fix 
I’m not a mechanic, so tread, lightly
Tools 🧰
Wrench
Extension 
27 mm socket
A Jack….are buddy
Jack stande … for safety. If you’re feeling bold, you don’t need it, choose wisely 
Amazon link:
ACDelco GM Original Equipment D1843A Engine Oil Pressure Switch https://a.co/d/4DfrOlz