96 won't start

My mom has a 96 GMC Safari and she told me it wouldn't start. We replaced the battery and it started. The next morning I went out to try it and the numbers on the odometer were going crazy along with the rest of the lights. Also the command start light was staying on insread of usually blinking. I took the battery and charged it (the new battery). Tried it again and it made a noise similar to a vacum. I tried it again and it started. I then tried it with the command start and again the vacum noise came on. The 3rd time with the command start it started. I have it running outside right now and am letting it warm up. Do you think the fact that is is -40degress celcius could be the reason? Or is something wrong? Altrenator or fuel pump maybe?

The "vacuum" sound you describe reminds me of the sound that a starter makes when the starter motor runs, but the drive unit does not engage the flexplate/flywheel. It may be a problem with the solenoid, or the drive itself. In either case, replacing the starter would cure the problem. Without actually listening to it myself, that's the best I can do. You might have an assistant watch the cooling fan while it's making that sound. If I am correct, the fan will not rotate. -40C can affect a lot of things, lets try to diagnose one problem at a time. ;)