My 99 Ram has a carter frame mount 4601HP lift pump installed. They wired it to a sensor in the block. The sensor acts as switch, and will shut off power to the lift pump when the truck is off.

Today, the lift pump continued to run even with the engine off. That tells me the sensor is bad. The lift pump, wiring, and sensor are remote from anything else in the truck.

The sensor is made by Nason, Part #SM-2A-25R

Can ANYONE help me? I was able to find one online from Nason, but its 4 weeks out and im not 100% sure its even the right part.

I tried checking online for the Carter lift pump kits, but none had an such sensor listed. Help?!?!

 

OK, well, i think i have it figured out. The Fuel pump cutoff switch, which is controlled by oil pressure, has failed. I have a new switch coming to me today! What a pain in the neck, i thought this stuff never fails! What gives?

I will update this thread when/if I get it fixed.