Car still runs after turning off and gauge lights stay on.

Make: Chevy Camero Year 1998 Miles 60000.

Had a Mechanic(Family Friend) come over little computer. There were no error codes. Before I called the Check Engine light came on. But when he came over the battery was dead I just drove the car 2 days prior. Barrowed the battery from my truck it started right up. Still no codes not even history which he thought was odd. told me to call him if it comes back on. 2 days later I went to start the car and it was dead again. I figured the battery was bad since I just charged it. Put new battery in the car starts but odd things are going on. I turn the car off and it still ran. got it to stop. pulled the key out and the gauge lights were still on and luminating.(Brake,Air Bag etc.) and I can hear clicking in the engine, mainly by the 2 Throttle cables again this is with the key out. I figured I would disconnect the battery since it seemed like everything was still on and that is why the barrtery was dead in the first place. Need help. I did donate under the name daniellehol.

Kristi Canziales