Q: Have a 2000 Jeep grand Cherokee Laredo 4.0. The voltage gauge is not working and it spits and sputters while alternator is hooked up.

Hi there. If the alternator is causing the volt gauge on the dash to stop working, then the polarity on the wires is backwards. Check the power wire to the alternator and make sure that its hooking up to the positive side of the battery. If its hooked up properly, check the voltage coming out of the alternator and make sure that its a positive charge. If the charge is normal, then check for AC charge on the alternator. The alternator should have no more than 35 AC voltage. If the alternator has more than 35 AC voltage, then the alternator needs replaced. The voltage regulator in the alternator is not working. If you need further assistance with the volt gauge not working with the alternator hooked up, then seek out a professional, such as one from Your Mechanic, to help you.