Alternator and Voltage Regulator Questions

Pretty much a comedy of bad parts. The new VR AND Alternator were bad. Got both today. Works perfect.

Simple tests that can be done. I will put them here to help others.

Vehicle and key off.
1. Test voltage at battery. Should be 12.7-12.9 volts. If not battery is low and needs charge or is bad.
2. Test voltage at “batt” connection on alternator, should be pretty much same as battery. If not wiring through bulkhead, gauge, battery cables are bad.

Key on vehicle off
1. Test voltage at input plug on vr, should be similar to readings above. If not bad wiring through/from ignition.
2. Test voltage at output on vr. Should be similar to input, If not bad VR
3. Test voltage at “fld’ Lug on back of alternator. Should be similar to reading above. If not bad wiring from VR to alternator.

Key on vehicle on.
1. Test voltage at battery. Should be 13.5 or greater. If not alternator is bad.

If tested in this order. It is simple to diagnose.

Tests to do on new parts.
Test new alternator in the store.
Test VR in the store. Make pigtails to attach to a battery in the store. Input to positive terminal of 12v in store, ground to negative terminal and multimeter on output and neg battery terminal. Output should be similar to battery being tested on. Parts store stuff is junk. Test it before buying. Don’t waste your time.

Thanks for all the help.