The yellow wire goes to the ground of the n2o noid...just replace the shift light with n2o noid.
If you have a msd box the white wire goes to the tach output on the msd box, if you dont have an aftermarket ign. box you can tap the tach sig. wire or put it on the coil - side like the ign. dia. without an msd box.
Grey is not used.
red is to a switched 12v. source...I have mine hooked up to the master n2o switch so it only "sees" power when the n2o is active.
i connected once the way i thought it should go, but then i armed the switched while having the ignition on with the car of and stepped on the gas and the solenoid still clicked, so im really lost cuz i thought that was the way.
ok i got it know, i think. but now i need to go buy some splicy things, so i can tap into the line from the Nitro that goes into the throttle position sensor, and the yellow one into the groung nitro. does that sound about right? and if i put a multi reader in the negative of the coil, what should it read?