Engine and transmission wiring

[BigFish]

I was trying to trace the mess that is the wiring on my truck today and one of the wires the previous owner spliced came loose.
The truck now sounds it's horn, hazards flash, and gear indicator flashes when I start the truck. Similar to what it does when taken out of park with the door open.
This wire in question will be the wire circled in blue in one of the pictures. The wire they had spliced (with no insulation of any kind) to this little nub of a wire, was a red wire. The red wire was routed back to the transmission and is tied into some other wire spliced with two wires going up and through the firewall, and a wire to the under hood fuze panel. There are two factory wires cut from the trans range sensor plug as well.
I'm in the process now of investigating under the dash to see where the red wires that route through the firewall actually go.
I'm guessing this was some sort of horribly executed install of remote start or alarm.
Can anyone tell me what's what here, or what I need to reconnect to make this thing drivable again?
I set up an appointment to get the alarm and remote start un-installed at a quality shop in town, but can't even drive the thing there for the moment.

 

[BigFish]

Upon further investigation, it appears the two dangling wires (yellow, and green with yellow trace) near the trans position sensor plug, are indeed the ones that once ended in the plug. For some reason they were terminated and red wires mentioned in my original post were spliced in.
I'm beginning to wonder if I can get away with removing the red wires and reconnecting the original wires and have it function correctly.
I'm going to investigate the red wires going through the firewall first and see what they actually go to before trying it.
Still looking for advice here, just wanted to add the above info.

 

[Topzide]

Is there an aftermarket alarm in your truck? Looks like some of the crappy installs that I've seen over the years! I prefer to install that stuff myself in my own vehicles. I installed a remote start in the DW vehicle. I peeled back the wire insulation, spread apart the wires, inserted the wire between strands and soldered! If I need to cut a wire, I cut it long enough and cover with heat shrink. Hope that you can get it figured out. I wish I could help more, but ensure of that connector.

 

[BigPapa]

What truck and I’ll see what I can find.

It would really help, since you can’t have a signature, (this is not just at you BigFish) if you’d state what truck you have in your post.

 

[BigFish]

Sorry, Definitely should have included that.
Truck is a 2006 2500 mega cab, motor is a 5.9, and trans is a 48re.
The guy who owned this before me either installed or had installed a remote start and an alarm system and it looks like a 2nd grader did it. Wiring is not my thing and even I can tell this is not right.
Anything you can come up with would be awesome.

 

[BigPapa]

Maybe one of these.

 

[BigFish]

I'll take a look tomorrow if I have time and see if those colors jive with what I'm seeing.
The wire in question comes out of the pcm plug furthest to the rear if that makes anh difference.
I was able to scrape just enough insulation off the wire to reconnect it temporarily and get the truck started. With that wire reconnected, it started and ran without the horn and hazards.
I'm worried I'm going to have to pull that pcm plug pin and reinstall with a longer wire on it to even be able to splice it back properly. I'm hesitant to do that until I figure out exactly what goes where to make this wiring as close to correct as I can.

 

[Topzide]

There may be just enough there to get a piece soldered onto the stub! I would recommend a separate solder flux and silver solder for a strong splice! Good luck. We're here to help in any way we can, whether it's wiring diagrams like @BigPapa was able to provide, to tips and tricks from others. Maybe give a general idea of where you're located, and maybe there is a member close to you that could lend you a hand with the wiring. I know if you were close enough to me, I'd offer up some help to a fellow Cummins "Nut"!

 

[BigFish]

I appreciate the info and advice. I agree there may be enough there to solder a wire back on. If I can't make that happen, then I suppose I'll go through the headache of pulling that plug and replace that pin so I can have a longer wire.
I first need to gifure out what wire originally connected there though instead of reconnecting the one the previous owner ran from there to the trans. I'd really like to put the trans position sensor plug wiring back the way it belongs and figure out what connects to this nub.

 

[BigFish]

Maybe one of these.

View attachment 142148

I'm going to have to look on the truck when I get a chance later, but judging by this diagram and what the truck was doing, im thinking it's probably the yellow/dark blue wire that goes from the park/neutral safety to the pcm plug.

 

[Ozymandias]

You can get a repair pigtail for the park/neutral safety switch.
Easier then trying to repair that mess.

Use heat shrink solder connectors for the repair, that's how it is done today.

https://www.amazon.com/solder-connectors-heat-shrink/s?k=solder+connectors+with+heat+shrink

Get a small heat gun for them if you don't have one, 20$ on Amazon.