Pete 579 no crank no dash powerup

[Lonestar10]

My dad's new truck a 2015 pete 579 was fine on Sunday when I fixed the engine programming was working fine. Today they go to start the truck and the dash doesn't lite up and it won't crank. But if you put key in run and jump the starter engine starts and runs but still no cecu.

They installed an apu shutdown wire to the ignition and I think this is the problem source.
Which I told him not to install in the first place and just install a run/stop toggle switch but I'm not his longtime friend and mechanic what do I know.

But in case anyone has other ideas ied like to hear em if this isn't the case.

[Nilao]

Does that model and year still use a ignition relay out on the passenger side firewall? You could check there, but when this truck ignition relay failed it would still crank just no dash gauges.

Also check the fuses, especially if they added a wire. And yes, these days I'd run the ignition sense wire to a ignition hot location on the fuse block using an add a circuit fuse adapter. These new trucks multiplex everything and tapping a wire then running a wire elsewhere could cause it to shut down everything on that circuit.

I could be off base here but get a power diagram for the switch and see what the wire they spliceg into just to be sure.

[Lonestar10]

I showed up in the shop after delivering a load and fixed it in 20 minutes it was one of the big plugins on the fuse box at somehow gotten knocked loose they couldn't find that all day yesterday I found it in 20 minutes lol

[tree98]

(04-22-2021 )Lonestar10 Wrote:  they couldn't find that all day yesterday I found it in 20 minutes lol

I've been on the wrong end of one of those a time or two

[Lonestar10]

I went in with esa could connect to cecu fiddled with that for 10 min once I found I could control cecu just fine I went into the fuse box by the clutch pedal with a test light poking fuses then moving relays around before I went to unplugging and reconnecting harnesses and first harness I touched suddenly dash lit up like a Christmas tree and radio turned on. Fully unplugged and reconnected and bobs your uncle everything worked perfect. Shook the connector never skipped a beat.

The connector was one of those with the plastic bar that acts as a lever to disconnect and seat the socket.

The connector with orange label tag. https://www.google.com/search?q=peterbil...1BGDdUjknM