Of which low pressure switch are you speaking? Engine oil pressure switch? If you're checking that, remove the oil pressure sending unit and temporarily put in an oil pressure gauge. If you're checking the AC low pressure switch, pull the switch from the AC low pressure line, Jumper the switch socket and see if the AC compressor comes on. If it does, you either have low refrigerant pressure or a bad switch. If you KNOW the pressure is up and everything else works, you have a bad switch.
With a fuel pressure gauge.
Check fuse Could be a bad switch
check to see if you have enough low side freon pressure and/or if the low pressure switch is working. bypass switch by crossing the wires of the switch with a paperclip to apply trigger voltage to the coil on the compressor,also check to see if there is voltage going to the low pressure switch,if these measures don't work,disconnect the high pressure switch to see if that switch is stuck and shutting off power thru the relay.
Check bulbs Check fuses Check switch
check vacuum lines to canister,light switch,check valve, Accuators
Water level in the radiator.
You will need a fuel pressure guage to check the fuel pump. The pump operates at 13 psi.
Check the fuse Check the relay Check the switch Check the resistor
Check the bulbs, check the fuse then check the switch.
Check to make sure that the dimmer switch for the dash isn't stuck on high, that will make the lights stay on. Also check the door switches to make sure that they are working and making contact when the doors are shut.
i would check if you have power to the motor from the switch
Check, Help/config > options. pressure should be at 0%. if not, your tablet pressure is not setted. IF 0% and not working, check the density, still not, your tablet pressure is not working all together, or not on sai.