Keyless Entry Problem on 94 Bonneville

The keyless entry system on my 94 Bonneville is not working right. Sometimes it works normally and sometimes when I press a button on one of my 2 remotes nothing happens. If I rap the remote against my hand, sometimes it will work but not always. I've put new batteries in both remotes and still inconsistent operation.

Can anyone tell me where in my car the receiver unit might be as I may just replace the system with an aftermarket unit and it would be a lot easier if I knew where the receiver was. I am just thinking that maybe the receiver might be going bad OR is there a relay in the circuit somewhere that might be sticking open and not closing when I push the buttons???

Also I know that there are 3 wire door lock systems and 4 wire. Does anyone know what mine would be.

Thanks,

Mike