2002 Gmc Envoy

Start by having the battery and alternator checked, free at most parts stores like Autozone, Pep Boys Etc. But you have to get the car there. You need (and should have anyway) a battery recharger/maintainer. Fully charge the battery overnight, the charger may tell you the battery is bad, or it will fully recharge and this will get you there for more testing. My assumption is that the alternator is bad and not charging the battery, or you have a bad battery, even if you got a new one, they can still come bad occasionally. Few Tips: There are lids on the top of the battery you can pry up and there will be holes filled with liquid, if they are not full, buy DISTILLED water and fill them up, replace lids. Low fluid will damage battery and prevent holding proper charge. Check your terminals and wires going to and from the battery, you can follow them easily from the alternator to fuse block, battery and starter, look for breaks, corrosion, loose, disconnected. The key will come out with the right power supplied, which I assume isnt happening with a dead battery. Should be fine even with a jump start, but will not stay good if either part is bad.