Many problems with 1996 Bonneville

[Keller0512]

Hello, I'm new to here and am hopeing someone could help me out with the problems I'm having with my car:

1. This just started when I changed the battery, the Climate Controll System is acting weird, all the controls on it work but it dosnt blow out hot air.
2. When I accelerate the oil pressure gauge goes from around 40 all the way to 120 and stays there until I'm stopped again. I've checked the oil, but its not low.
3. The radio dosnt work properly. The steering wheel controls are the only controls you can use to opperate it, otherwise it will shut off. The display also dosent show up.


Any advice/help is greatly appreciated. Thanks,
-Rich