[dave92cherokee]

You can also just take the alternator out and take it to auto zone or advanced auto and have them test it for you. Chances are it will probably need to be replaced as that's what happens to them sometimes when they start to go out. How long do the power surges last when they happen is it just a few seconds or does it last until the car is turned off and back on? If it lasts for a while then if you get lucky you can drive the car to them while it's happening and have them test the entire charging system while it's happening.