well my wife was driving my truck on Sunday from Iowa to Colorado, after 2 hours the battery light came on, she made it home then shut the truck off. I turned it back over later that night and the light is gone, I took it to GMC to see what the issue was and the altenator is on the low side on putting out juice. Now today I went to get gas, I was at 1/4 of a tank. After I filled it up the gas guage said low fuel then started climbing up, then it would go all the way down again. Finally when I got to work the gas gauge was ok. Now can the since the altenator is going bad can this affect all the electrical sysetms in the truck? like the fuel issue I had today?