Bad voltage regulator?

[76GMC1500]

Does your alternator have 1 wire or 3 wires to it? If it's a 3 wire, you need to find which one is for excitation voltage. Hook a volt meter up to the main outlet wire and start the engine. Connect 12volts from the battery to the excitation lead and if your voltage jumps to 14-18v+, your voltage regulator is bad. If the voltage stays the same, something else in the alternator is bad.