cummins lift pump will not run HELP???

Did you check the fuses in the battery box

 

there is also a fuse, in a fuse holder ahead of the pump up near the ifsm system, just above and to the right of the air compressor, it will probably be painted red and zip tied to something. should be a 20Amp(?) blade fuse there, check it and I bet you will find your problem.

 

Or possibly the ECM, i've seen this more than once. If you make a break out harness to apply straight power and ground to the pump this will answer your question if it's the ECM or pump.

 

most likely the fuse is failed as said a few posts above, check the fuse should be on the wiring harness between the ecm and air comp. head. itll be zipped tied and painted red. 10 amp fuse.

 

with the fuse blown thats a sign the pump is going out

 

normally if the pumps starts going bad, or goes bad all of a sudden, it will put a load on the fuse and pop it. most likely if that was the original red pump, it is bad anyway and if there wasnt a core charge, trash it.

 

One of my I am Screwed Engines [ISX] had the same problem, no power to the pump. It wound up being the relay that is before the fuse. I tore that wiring all apart to figger it out too !. Had power going in but none coming out of the relay. Called KW dealer and they said they don't have 1. Said the last time they needed 1 they went to NAPA ! I'm like WTF ??!?!!? Went to NAPA, yeppers 29.95 and took her home plugger her in and we had power. Thot this might be worth having a spare in the glovebox no?

thought I'd share that to help someone who has probs in the middle of the nite. If you own and/or drive an ISX, if you don't already know, some day you will, that engine don't run if the lift pump don't run. One of the multiple reasons I dislike that red POS.