I think my low pressure switch has gotten way out of calibration and needs changing out, if I lower the pressure enough for the ride to besmooth with just me on the bike (180#) the red light comes on, the light doesn't go out until there is at least 35-40# on the guage, at which point the back end starts to get bumpy.
In the last 10 years I've been all over this bike like a bad suit and have yet to find a switch or any wires for that matter that would control this light, even the rebuild threads don't showa switch and given the warning around the light, to "reduce speed to below 50mph" this isbecoming something of a pain in the a$$, pun intended.
The switch is back next to the rear master cylinder. You can easily disarm the thing by grounding the wire attached to the switch. That will kill the light but leave the wiring in place in case some time in the future you want to restore its function.
Yep, like Paul said the sensor is on the bracket that holds the air junction for the rear shocks. The bolts that hold that bracket in place pass through the frame and thread into the rear master cylinder.
Before by-passing the sensor I would check to make sure you have a good connection. If that doesn't work...then yeah just ground the wire and enjoy the ride.