2014 5.0 Engine Harness Question

[Roger Bell]

Good Morning Everyone! Been a while since I have posted. I am in the middle of my next project - putting a 2014 engine and harness into a 2011 car. One interesting thing has come up. On this 2014 engine harness, there appears to have been a previous mod or repair that I can't seem to figure out. At the injector #5 plug, someone has grafted in a wire that goes back to the firewall, and then through the firewall in the vicinity of the brake booster. The work was done in a very neat and professional manner, but I haven't been able to figure out what it is or why it would have been done. My theory is either some sort of repair due to a harness problem, or perhaps a take-off to provide signal for something else? The donor car is badly crunched and I cannot get into the drivers side area under the dash to try and trace the wire, until I cut that side of the car apart. So for now, I'm hoping someone on here might know what this might be? The pic shows the harness (on my shelf currently) with the grafted wire at injector plug #5. Thank you all in advance for any responses.

 

[Midlife Crises]

It could have been a signal for a shift light.

 

[Juice]

Going from memory here, injectors get 12v power, this is common to all 8 injectors.
The other wires from each injector go to the pcm individually for injector control.
So, is the mistery wire going to power or ground/trigger side of the injector?
That would be an odd place to tap into power.
So if it is to the ground side of the injector, it could potentially be an RPM signal tap for some gadget, maybe a shift light.

 

[RED09GT]

Tach signal, window switch, or something else fun.

 

[Roger Bell]

Thanks everyone! This seems to line up with my suspicions. I'll install everything and test. I'll send a further update once I'm up and running. If I can avoid buying a new harness, I will.