1997 Oldsmobile Bravada car wont start

I've got a 97 olds bravada, i've been having problems lately. It all started with the rpm gauge. I'd be at a complete stop and it would start reving up to about 2100 and then falling back down almost to the point of the vehicle dying. My headlights would dim and brighten with the rpm's as well. I'd step on the gas there would be a small pause and it would stutter and go. Then sometimes when I turned on my blinker it would just die. If I kept my foot on the gas though it would catch and be fine. Then the starting problems began. When I turn the battery on sometimes the dash lights won't come on, if thats the case theres no chance for the vehicle to start. If they do come on however it starts no problem. When the lights fail to come on I still have power to everything. I replaced the battery and nothing. Now my turn signals wont even work on the dash and outside of the car my hazards work fine. What is going on! The army's got me stationed at fort wainwright in fairbanks alaska where it gets -50 so im sure that doesnt help any but im tired of doing pushups for being late to formation in the morning so any help would be appreciated.