2021 Pete 389 w/Cummins X15. 85K miles. Issue just started this morning.

2021 Pete 389 w/Cummins X15. 85K miles. Issue just started this morning.

What would cause a power disruption inside the cab while the ignition is OFF? If I open the doors, the dome lights don't come on, the dash/odometer doesn't light up, no power to the headlights, running lights or hazard lights. All these used to have power with the ignition off before today.

When I turn the key ON, everything comes alive with no issues...except the information display clock and radio clock have to be reset, just like the batteries were disconnected. It will start and run fine. Voltage is right around 14.1V with the engine running. No dragging in the starter while cranking and batteries seem strong.

HOWEVER, if you cut the key off while an accessory is drawing power or the door is open, everything works like it should for as long as the current draw is in use. When everthing is turned off and I shut the door for about 30 seconds...then open the door again, I'm back to no interior lights or power to any accessories...and it blanks the clocks again. Turn the key ON...everything comes back.

I have already checked every fuse under the dash and also in the box on the firewall. Nothing is amiss there. Is there a circuit for standby power that is supposed to keep power on tap to the clocks and accessories whenever the key is OFF for a specific duration? Does something need to be reset?

I have already checked all the battery terminal connections. All are tight and zero corrosion. I also hit the test button on the ignition protection breaker inside the battery box...and reset it. Out of ideas except taking it to the dealer.

 

Yes, sure did.

 

Shouldn't I be getting some type of message or LVD light come on if that's the issue? If I recall that system has a control box mounted somewhere inside the sleeper on a sleeper truck. Mine is a day cab (probably should have mentioned that). Where would I look for it?

 

Update: So I took my battery tester to work with me this morning. I disconnected all terminals and load tested each battery. All were within acceptable. I reconnected everything exactly how it was...and I can only assume doing this reset something in the truck's ECU. I opened the driver's door and the interior lights and dash all lit up like normal. Issue has been resolved for now.