Kenworth T2000 - Air Tank Light On Tank Full 130/140 psi

Drain the #### thing. If light refuses to go out with tank valves wide open...

Take it to a shop. I think the light itself is bad. Or the sensor that drives it. It makes no sense on full tanks.

 

probably the pressure sensor for the tank but that's a weird one cuz it shouldn't throw the light on possible the gauge is just bad

 

Is the buzzer on as well? If it is, I'd say its likely the pressure switch or a shorted wire from the pressure sensor. If the buzzer is working properly, then you have an electrical issue related to just the light.

 

Depending on the year, if this is an older truck there is a module on the passenger side down under by the air tanks, this thing takes the air pressure and some other info and sends it to the dash via multiplex, you might have poor connections or a leak in this module.
Its a poor location for electronic components.