Does anyone know how to hook up the MSD RPM Activated window switch for use with nitrous? The instructions say to ground the relay, so i did this through the microswitch ground. My tach signal goes straight to the white wire on the guages (this is the tach output and i dont think it is the problem) twelve volts is given to the window switch by the same switched 12v that the arming switch is hooked up too. and the ground to the msd component itself is done through a connection to the driver's side fender (im pretty sure this is a good ground) i heard you need to ground the solenoids along with the relay but im not sure if this is correct...Any help on how someone got their setup to work is appreciated
Did you cut the two wire loops sticking out of the MSD window unit so that it operates in 4-cylinder mode? That is the only way it will work on LS1-based ignitions systems, trucks included.
I use the window switch to provide a ground for the sensing part of the relay, and use the higher current switch part of the relay to power the solenoid. And, as you did, I also prefer to have the master arming switch provide the power to the window switch.
The white wire coming from your tach should be okay. If not, just splice it into pin #10 coming out of the PCM. Its also a white wire.