Have you ever pulled the wires out on your nitrous solenoid? Here is a how to on fixing this problem and saving some money.
Step One: Hold the base of the solenoid with a pair of channel locks or in a vise. Remove the nut on the top of the solenoid. The coil and cover will come off as one unit. Slide the coil out from the bottom.
Step Two: There will be a piece of tape on the bottom of the coil covering the wires that you need to peel back. Once you have the wires exposed you will need to shave off the clear coat on the coil wire. Cut off a piece of coil wire (you can get this at any radio shack or electronics store) about 4 inches long and shave the clear coat off bothe ends about 1/4 inch long.
Step Three: Solder the coil wires together. Wrap the new coil wire about half way around the coil. Retape the wires over the same way they were taped before. Heat shrink the wires together for stability and to prevent shorting out.
Step Four: Thread the wires back into the shell and out of the hole  Replace coil and cover onto the base and turn it to the position of your choice. Replace the nut and test the coil to make sure it functions properly.
I hope this helps out any of you that have ever had this problem.