This is not normal and could be indicating that your fuel pump is either on its way out or your fuel filter may need changing. (The light should be out at all times unless there is a problem that’s causing pressure to drop below 5 PSI.)
This is normal. The light will come on with the Key in the ON position, but not running. This is because pressure is less than 5 PSI with the engine off. Once the engine is started you will have fuel pressure above the 5PSI warning point and should trigger the light to go off. If the light is on while the truck is running, then your warning system is working and you pressure must be less than 5PSI. (This could be a clogged fuel filter or a lift pump/injection pump issue.)
Call our Diesel Experts at 1-888-343-7354 to see if this is something we could special order for you!