97 Saturn SL2 Electrical Problem?

On my Saturn, it happens in 2 places. If it happens when the vehicle is cold, When accelerating, the Transmission will be stuck in D4. if the short happens when the car is hot, you will be traveling about 75 MPH on the interstate, and the guages will go dim, and the volt meter will bottom out, like you turned the key off. It is the same response when the car is cold. It is like you turned the key off, but the engine still runs fine. The only difference I have found which is major is when it is cold and it acts up, the volt meter bottoms out like the key is turned off, and it will not shift. When hot at night, you can see all the lights go dim, the AC blower motor slows down, etc. Any ideas? ALREADY REPLACED THE IGNITION SWITCH UNDER THE DASH.