Transistors to switch 12V 2A
This is simple, simulates nicely, and should work just fine.



R1 is the 2 ampere load, 10 millihenries is a WAG as to the motor's inductance, and I just semi-randomly picked  the FDS6576 out of the LTspice library; almost any P channel MOSFET will work there. Likewise, there's nothing holy about the 2N2222.

Here's a link to the LTspice circuit list if you want to play with the circuit.