why does the voltage gage at times flutter back an forth on 2000 Chevrolet Silverado 2500

I notice that my lights flutter an the voltage gage go wacky at time , is this a short somewhere?

Asked by for the 2000 Chevrolet Silverado 2500
You are absolutly correct. There is a short in the electrical system. Start be checking the battery terminals for corrosion or loose. It's lickly related to your battery or alternator. If you feel motivated remove them and have them checked. I'm not sure where else you can go to have this done for free but Firestone perfoms an electrical system check on the battery when you get your oil changed. This is done at no charge.
battery is good alternator is good on back of truck a box unit like thing with wires for lights an tow pkg, brake lights an a lot of plugs going to it I think it may be the problem?