Battery issue

Sounds like a battery cable failure from corrosion. Very common for that because of the GM cable designs. Start with cleaning the connections on the cables at both ends and check to be sure they are still solidly attached by tugging on them. Next would be a bad battery that is shorted, to test that use a voltmeter and test it.
https://www.2carpros.com/articles/how-to-use-a-voltmeter
You want to see voltage of 12-12.6 volts. Then while you are watching the voltage, have someone turn the key to start. The voltage should drop down to around 9-10 volts while cranking. No change = poor connections. Drop of the voltage to lower than about 10 volts = bad battery.