Truck won’t turn on

Detroit or Cummins?

 

639-FMi 9 is power supply to ECM disrupted.
I’d start there.

 

Unhook the batteries for a couple minutes on autos.

 

@pushbroom
Hopefully can help

 

If your having power supply issues to the ECM, it will try to start all day but never turn over.

On Cummins there’s a power wire from the battery into the OEM side of the ECM harness. On Detroit it may be a little different. Usually when it’s an ecm power supply issue the abs light and the check/stop engine light all come on together. That’s because there’s a disruption of power to the computer that controls those things!

start here, find the disruption of power, look good and hard to see if there is an external wire that comes from the battery to the ecm for power. This can usually be identified by the in line fuse close to the batteries and then by looking at the direction the wire goes once it leaves the box. These lines can become ice blue with corrosion over time and cause major resistance resulting in power disruption. You’ll have to peal back the wire loom and inspect. Test the fuse on that line if you got one.

you’ll have to pull the plug part of the harness from the ecm, figure out which pin provides 12v power to the computer and test for power with the key turned in the ACC mode.

but before you do this, I would test EVERY fuse in your fuse panel. Especially the ones dealing with ignition and etc

 

Whisper to it with a sexy voice. Jk battery off for 30 minutes often does help though .