Mystery plug under steering wheel

I found this plug under the steering wheel in my 99. Does anyone know what it goes to? It has 12v between the contacts with the ignition in the ON position. It is not active in ACC or with the key out. Green is positive and brown is negative.

 

Really, you found juice in that plug? I swear that's the one I tried to plug my lighted ignition ring deal into. Now I wonder if the bulb was bad in the ring? I'll have to double check now

 

I had another plug for the lighted ignition ring, so that's definitely not it.

 

Oh really? Okay, I only found one empty plug but I am base model. But it sounds like in my case either of those then have power and should work for my ignition ring. Good luck with your question.

 

The one pictured only has power when the key is on. Using that for the ring would kind of defeat the purpose wouldn't it?

 

Yeah, yeah it would.

 

Is it aftermarket or tied into the original factory wiring harness?

 

How else would you know if the truck is on?

 

Oooo, I think I found it. Connector EF1 is more rounded like the one in your picture.

 

Electric locker?

 

Eh, maybe not. EF1 is in the engine bay.

 

It runs into the wire loom with the rest of the ignition wires.

 

It doesn't look like any Toyota connector I've seen before. It has round barrel pins.

 

That's what I was thinking. It doesn't look like anything under the FSM. I think the only thing you can do is trace the wire. Does it look like someone added it in, or is it part of the factory harness?

 

It goes into the wire loom with the factory harness, but I guess it could have been put in there after the fact. I can't really tell where it goes other than back with the ignition wires.

 

I don't think there's anything else you could do besides follow it as far as you can and see where it potentially goes.

 

So I have determined that the plug goes to my South East Toyota installed security system. It is referred to as the "Theft Deterrent System" or TDS. I compiled the documentation on the system a while ago since it was hard to find correct info. I'll post my documents here for future reference.

The green and brown wires at the connector change to orange and yellow which are part of the starter disable system.