1992 BMW 325 gas gauge, coolant gauge, radio, info computer

There are several things that it could be but first, there's a circuit board in the instrument cluster that controls the service indicator lights, which also back feeds coolant gauge and fuel. Try that first, let me know what you find/

I have come to find out that the wipers are out as well. All of my cluster indicator lights work. Those things combined with the windows only working when door is open make me think relay or multiple problems. If you still think I need to check that board, how exactly should I go about that. Should I check that it is getting power, cause I assume it is or the indicator lights wouldnt work. I wish I knew all the relay locations and how to test them. I feel it prob will be multiple issues. Windows, wipers, gauges(mph and rpm work fine), radio, its like half the car is down. Thank you by the way for your reply. If I can save going to bmw shop, you can expect a nice donation in your future.