How to fix a malfunction regarding a 2005 4x4 z71 Tahoe that has high battery voltage, a rear hatch brake light that's shorted out along with the rear hatch windshield that's no longer operational. The radio's red indicator light no longer is on even though the radio still works. Every once in a while the truck doesn't start once it's remained off for duration of time unless relay fuses are switched around and vehicle is allowed to remain shut off for a moment then re-started.