That means that your program isn't turning on the relay for some reason, or the signal isn't making it to your sidecar.
Download the FRC Diagnostic Window program located here:
http://thinktank.wpi.edu/article/138
You can use it to try manually turning your relay on/off and to see what the pressure switch is reading. The relay should obviously switch on and off when you tell it to in the diagnostic window. The DIO for the pressure switch should read "0" when the switch is plugged in properly and the pressure is below 95 psi.