Tail Lights, license plate lights, and OEM trailer socket blows fuse

I've read all of the other threads, and reviewed the electrical diagrams.
I unplugged the trailer socket and plug, license plate bulbs, and both tail light assemblies. I inspected those bulbs, wires and connections, and found no frayed or broken wires.
The fuse still blows immediately when I turn the light switch, even with all of those items disconnected.
I'm assuming the short is either in the switch on the steering column, or in the wires between the connectors in the rear and front of truck (visual inspection found no obvious breaks in the wire).
Questions:
1. What should my next steps be?
2. What other tests can I perform with a multimeter or test light?
Note: I am waiting on delivery of a Short and Open Finder Circuit Tester/Wire Tracker.

 

I see no mention of headlights or fog lights. The switch operates relays located in the main fuse box behind the battery. The short could be in the engine bay between the headlights and fuse box or try swapping in a new relay.

 

Which fuse? There is more than one.

 

The stalk multi-switch completes the circuit to ground, it does not provide fused power to any of the circuits it controls.

 

The 10 amp fuse (#3) in the under dash fuse box.
Headlights, fog lights, brake lights and turn signals all work.

 

10 amp (#3) in under dash fuse box

 

The only things that fuse feeds is the park lights, tail lights, license plate lights, trailer brake controller plug, and dash indicator if you have a Canadian truck. That fuse does not feed the trailer light connector.

https://www.customtacos.com/tech.ol...6toyewd/06toypdf/ewd/2006/tacoma/h/em01d9.pdf

https://www.customtacos.com/tech.ol...toyewd/06toypdf/ewd/2006/tacoma/h/em01d40.pdf

Edit: Is there any chance the truck didn't come with a tow package and some Billy Bob wired the tow lights?

 

It is the taillights and license plate lights that are out. I only knew because I got pulled over for it. The break lights still work.
I wrongly assumed the trailer plug would likewise be out, but never tested or used. All wiring is original, as I've been the only owner.
The attached photo shows the fuse that blows as soon as the lights are turned on, even with tail light assembly and license plate bulbs disconnected.

 

Going to be tuff to find. Unplug the front corner park lights and inspect the wiring at the trailer brake controller plug near the left kick panel.

 

Yes, and it blows as soon as the lights are switched on, despite them being unplugged.

 

10@1D harness is my guesstimate

 

Stereo install recently?

 

Do you know how to de-pin the connector? Disconnect 1D, de-pin #10 green wire. Reconnect 1D without the green wire, place new fuse, switch n verify.

 

Depinned the 1D #10 (green) wire, installed a new fuse (TAIL 10 amp), and it still blew upon turning light on.

 

Nothing new installed. Everything OEM.
Did bottom out in mud 4 months ago.

 

Good job. Now you know the problems not in the rear lights. Now try depinning the other wires in post #13 above.

 

Without replacing green wire on 1D; De-pin on 1C

 

Acknowledged. Assume one at a time, repinning the ones tested when the fuse blows, and when it doesn't, that'll be my problem wire (circuit). Thanks.