1996 Isuzu Rodeo Question Are these related issues/how do I

I bought my 96 rodeo in June and the check engine light was on, however I had it looked at and it was a code error that I didn't get fixed. It started recently that when I slow to a stop, the rpm's surge about 3 times before finally downshifting for about 2 weeks now. Well now the brake, voltage and air bag lights have been flashing on and off since yesterday morning and my vents aren't working. The air bad light flashes a few times and then goes away, the brake light goes on and off, and the engine light and voltage light are steadily lit. At first I thought alternator but now I'm unsure? My first thought would be to check the fuses and go from there but I don't know what to do anymore.