I have after market oil pressure and oil temperature gauges since my stock oil gauges don't work and they stopped working. I don't know why since they came with the car when I bought it and I don't know where it connects to. If they are connected to a fuse in the fusebox, which fuse would it be connected to?

(They were working when I bought the car)

 

You gauges probably share a common +12v source (which is why they died in tandem) but who knows where the installer tapped in to get it.
You'll have to do some hunting to find out.

 

Pull the gauges out carefully, and follow the wires. You're bound to find something...

 

Alright well I can see a single red wire going off the the bottom of the drivers side and I'm suspecting that it's going to the fuse box as I've thought before. If it is that wire going to the fuse box, the red wire plugs into probably a metal prong in the fuse box because I can pull it out and attached to the red wire in a metal piece with a slot for something metal to go inside of it.

 

is this supposed to be a question? look at the back of the gauge. follow the wires to where they plug in. make sure they are getting voltage and the signal wire is hooked up (unless its mechanical, then the wires would only be used to illuminate the face).

 

pics will help alot, since this isn't anything factory guesses are just that. it should be pretty conclusive if you follow the wires and use a voltmeter to see if you are getting power/ground.