2013 V6 4DR 4WD - Rear Tail lights not working

Hello all, new to the forum and hope someone here might have had a similar problem but only found an old post that had no resolution. So far here is what I've found out on my Taco with only 83K on the ode:

• License plate lights do not work either (same circuit I believe)
• Voltage to both sides of external pins on #3 fuse (cab fuse box) when lights are on
  • 0 voltage when lights off
  • Ground was to steering column

Moving to the back

• Trailer Plug 11:00 (tail power) and 7:00 (Ground) Pins show voltage when lights are on

TL assemblies where green wire is taillights and white is ground (positions 2 & 3 in pigtail)

• 0 volts when lights are on.
  • Turn ignition on and left turn signal (yes I'm on drivers side)
  • Blinker voltage when probes on pins #1 and #3
• Repeated on Right side

This makes me believe the ground is good there on both sides.

• Checked wires on both light assemblies from pig tail to LED socket plug

Questions to the group:

• Should I even get into the license plate lamp connections?
  • I'm guessing that green will have no power and ground will be fine.
  • I am also assuming that a bad ground in that will not have any impact to the TL assemblies circuit.
• Would next step be to pierce the green wire where it come out of the cab below the drivers seat behind the undercarriage grommet and check for voltage while lights on?

I have seen there is a big connector towards the front of that grommet inside the cab that would at least let me know if it is after that connector.

• If I have to get access to that main connector, does the seat need to be taken out or just trim and roll the carpet back??

Thanks to all in advance!
Marc

 

Have you checked the TAIL Fuse (10A) in the interior fuse box?
Do the front tail lights work?

 

Yes position #3 fuse is the Tail of which I check both sides (pins) of the fuse for voltage which it had, when lights are on. This tells me it not the relay, I believe..

All front marker lights work...

 

So you either have a broken wire or an issue with the interior fuse box.

See if you have power at Connector 1D Pin 10 (Green) with the tail lights on.
If you do the the wire is broken somewhere between there and the back.

 

Thanks that is what I needed.

Do you know which (or if) there is a ground pin on connector 1D? I could then ohm 1D,pin 10 and ground pin as a sanity check backwards to the tail ass,em. Don't know if LED light circuits prevent that with transformers etc...

How hard is it to get to that connector? Do I have to remove any dashboard facia or just skip morning yoga because I'm going to be doing all sorts of crazy poses on the floor board (sideways neck stance, belly down head spun 180 pose)?

Do you think I should check the license plate stuff at all?

 

I'm not a fan of Ohm testing power and ground circuits but yes there are several grounds on 1D, here's a pinout of 1D.

It's on the front of the interior fuse/junction box, shouldn't be very hard but you may need to remove the knee bolster which isn't difficult.
Ignore the circled fuse, 1D is the connector that's circled in red.

 

If you have nothing back there and have power at 1D Pin 10 it has to be between there and the first splice which branches to the Left tail light so no need to do all that.

 

I agree with that logic.

I see a connector downstream that will be another isolation spot Do you have any reference material if that is just the same pin configuration of 1D?

 

There's no other inline connectors on the tail circuit (see the diagram), the wire goes directly from Connector 1D to the splice in the rear.
When there is an inline connector it shows up like this on the diagram, connector number is in the box and pin number is on the side.

 

Pardon my ignorance as I am not great at reading wiring diagrams. Where is the connector in this diagram that goes to each of the tail light assemblies, wouldn't they be in the diagram two posts above? I probably don't know how to translate he little writing in the paratheses across from the G (Green).

Trying to learn a bit more about diagrams, so thanks in advance..

 

No worries.
There isn't a connecter per se, they are splices. It's a place in the harness where two or more wires are joined together and sealed with heatshrink.
Splices show up as a circle on the diagram (circled in red). Unfortunately Toyota does not give us splice numbers or locations so I can't help with locating them in the harness.

The numbers in parentheses () (circled in blue) by some wires designate various options which can be found in footnotes on one or more pages of the diagram. In this case we see that (*3) is with LED tail lights and (*4) is with incandecent tail lights.