I have a wire coming from the car battery positive terminal. It is 12v DC. I want to split this wire to two other wires. I cannot connect another wire to the positive terminal. Will splitting this wire cause the voltage to drop to 6v each wire? or will they pull a constant 12v each?
No, each will carry 12v. I wouldn't advise physically splitting the wire though - you loose the insulation which is dangerous and you reduce the size of the wire which means that it may not be suitable for high current and could melt.
They will each have 12 volts. But the split wire may be too thin for the current. Instead, connect the wire to your first load, then a wire from there to the second load.
Splitting would not reduce the voltage, but you have to check the load and make sure that wires are adequate to handle the currents involved.
