24 Prime coming together...

The unit arrived. @AddMoreGas - can you please walk me through how to wire? Appreciate your willingness to help.

 

Now that I see one of these harnesses, I can help.

Tools/Parts needed to do the job (correctly):
1. 3-in-1 wire crimper, cutter, & stripping tool (or individual tools to do each part, but the 3-in-1 is better if you rarely do wiring work)
2. 22AWG heat shrink butt connectors (like this: 18-22 Gauge Watertight Heat-Shrink Butt Connectors, 10 Piece)
3. a heat source (lighter, heat gun, soldering iron, etc.)
4. dielectric grease (not super necessary, but it's best practice to use it)

1. Cut the gray wire as marked in red to remove the extra section. Leave enough so you can still splice the parts of the two gray wires still connected to the plastic ends together to match all the other orange wires. I don't know if it matters, but, just in case, mark which side of the cutout gray section went to which connector so you don't reverse it later(the A/B stuff in the image). I doubt it matters, but better safe than sorry.

(click image for full size)

2. Strip the ends of the gray wires still connected to the plastic.
3. Put a dab of dielectric grease on the end of each exposed copper wire
4. Use a butt splice and the crimper to connect the gray wires together (search for a youtube video if you've never done wire crimping before)
5. Use your heat source to shrink the ends of the butt splice until they seal(a little grease should squeeze out as they do). Try to keep the butt splice separated from the rest of the wires so you don't burn them.

6. Now take the section of gray wire you cut away and strip those ends.

7. You have a HEV, so find wire 6(marked in blue on the image). The gray wire is number 3, so you're going to want the second to last orange wire on the same row. If you have your shifter out while doing all this, you can double check by looking for where the purple wire goes into this new added harness; that's the wire you're going to want to tap into.

8. Snip the 6 wire in the middle of the span and strip both ends.
9. Use two butt connectors and splice the extra section of gray wire you cut away in step 1 to the ends of the orange wire you just cut in step 8. Use a little grease just like step 4.
10. Use your heat source to seal up the two butt splices and you're done.

Unplug the harness going into the parking brake switch and insert this new one in between and you should be good to go.

Hope that all made sense.


(The dielectric grease and using heat shrink instead of standard insulated butt splices is a bit of overkill, but we buy Toyotas for their reliability. Why introduce a potential problem years down the road from sloppy work when all it would take is a buck or so more money and an extra 10 minutes of time?)

 

Thank you very much @Hammersmith, here is the outcome of my wiring. I don’t have the heat shrink on hand, will redo when it arrives. Let me know if this looks good.

 

Seems good. Real test is plugging it in and seeing if it works.

The proper way is to pull the lower center dash trim* to free up the center console trim cover(the whole piano black section including cup holders and hidden storage compartment), but I think you might be able to get away with just starting at the back of the center console trim cover and prying it up just enough to get at the parking brake connector. You'll likely need to remove the shift knob, but that just unscrews.



*the part of the dash trim just above the USB ports that also goes up part way the steering column - it has the little grille for the cabin temp sensor

 

It worked! Plugged in and everything came to life. Now just need to button up and clean up wiring, thank you everyone for your help!

 

I was thinking. But first im an idiot. I know nothing about nothing. What happens if i bridge the seat belt wire to the hold button wire.