MrMoMo
That's not rust, it's Canadian patina...
If it is hooked up incorrectly it will always read wrong.
What does it do when the engine is not running, and you turn a load on... does it go positive or negative?
Is your alternator hooked up the correct way?
What does it do when the engine is not running, and you turn a load on... does it go positive or negative?
Is your alternator hooked up the correct way?