i have an aftermarket oil press guage. it was hooked up when i bought the car but it drained the battery. how do i hook it up so when i shut off the car it shuts off? anyone have a diagram

 

What brand of gauge is it? is it electronic or mechanical (i am assuming electronic)

Are you certain the gauge was the culprit? If you have a multi-meter there is an easy way to find out, disconnect only the power wire at the gauge, set your multi-meter to read DC Amps put one lead on the wire feeding the gauge the other lead on the wire going into the gauge (so the multi meter is in line between the gauge and the power source) and see what the draw is, it should be very very low.

Another way to check is see if there is 12V + on the red wire going into the gauge with the key off, if there is move the red to an IGN wire

What I would do it locate the power wires from the gauge, there should be a ground (usually Black) a Power wire (usually Red) an Illumination wire (could be really any colour) and if it is an electronic gauge there will be the signal wire.
Make sure that the power wire is wired to an IGN wire I am not to sure what colour the IGN wire is on your car (I am at work so I do not have access to my diagrams atm) if everything else was/is working fine that is all you should have to change, while your there it wouldn't be a bad idea to check on the connections and make sure they are good, I prefer to solder all connections but to each his own.

Let me know how it works out
Mike

 

hook the power cable to another component that also shuts off when the car ignition is on the off position...like ur stereo or something..doesnt matter