Great thanks dc42!
I think i am going to have to give the truck computer an altered signal while the arduino is controlling the solenoid. The signal i will send needs to be analog as if it was coming from the pressure signal. I believe i will need to send the truck computer a signal of approximately 1 volt. Since the arduino only does pwm i need to put in a low pass filter utilizing a cap and resistor correct? Also because i have changed the pwm frequency to 167 hz did that affect all the pwm pins? Any recommendations on resistor and cap size for the filter?
Thanks again!