You need to figure out what is wrong with it first. Could be the button switch, power suppy, solenoid, cable, etc. If you are handy, you can try bypassing the switch, jumping the solenoid, or maybe checking the cables.
yep - you should be able to pull the switch out, and then test the output wire - see if it is allowing juice out. the switches can be lame (my fuel switch likes to be stubborn).
i dont know how hard it is to access the solenoid back there, but if not hard, you could hit it with a test light while someone hits the switch (or you use the trunk popper on your alarm if you have one) and see if you have juice getting to it.
i dont know what they cost, but if insane, you could retrofit a universal 20 buck unit....