Im trying to find out what's wrong with the jimmy?? The instrument panels lights stay on(abs, security, low fuel, seat belt, and airbag) and my fuel gauge won't work until I get to certain rpms and my ac and heater kick on and off any help please its a 2000 Jimmy with 4.3 vortec I've been told its my battery/alternator or a short in my wiring. When I press the brake all the way down the lights go off and fuel gauge works but the motor sounds like its cutting out then goes to ideling rpms. What is wrong?? Also earlier today I went to start it but it started fine then the motor shut down. I unplugged and plugged the fuses back in after checking them and it started right up and ran fine.