My 1996 Toyota 4Runner is equipped with a factory tow package; however, I'm unable to locate the plug for trailer taillights.

As far as I know, your trailer towing package does not include a circuit for trailer braking. These packages normally only supply taillights, brake-lights, and turn signals.
RV sales and service dealerships should be able to help you.
God bless your efforts.

I don\'t think it has wiring provided in the factory for the tow package either. Looking at the schematics, they appear to be different with no provision for connections. The aftermarket have a wide variety of tow packages available which are simple enough to install if you ability.

Threr is one which you have to drill a large hole in the rear bumper to fit the receiving end of the connector. This is designed so that a wide selection of adaptors can be plugged into it. The adaptors are designed to fit the fixture in the bumper and the other end is shaped to plug into what ever connector you are towing. You will find this knid of fixture on nearly any factory package.. (NO WIRES DANGLING UNDER THE VEHICLE.) additionally, when not in use, there is a spring loaded cover which closes over the fixture to keep contaminants from entering Although I am a Nissan Master techniton, I chose a long wheel base 1 ton long wheel base cab and chassis Toyota with a 3.0 V-6 which I opened the back of the cab and installed a sleeper. Then built a flatbed with removable sides. I use this to pull my Nissan 300Z race Car. I have one of these fixtures on my truck because I don\'t always use the same trailer and the connectors to the trailer for the lights and electric brakes are different. The kits come with a controler for the electric brakes which you can mount where ever you wish and the controller has adjustments to control sensitivity of the trailer brakes so you can adjust the trailer to stop with the truck about the same time instead of wearing out your brakes from the extra load. With my Toyota loades with an extra engine, transmission and diff. Air compressor. Generator. Tool box, pop up tent, oils and other fluids and other misc Items. Between the trailer, the truck and it\'s load it grosses out at 11,800 lbs.When we go to Texas world speed way, we take 45 south where where there are very few cops. We cruise at 80-85 mph in the truck without a problem If the trailer brakes don\'t work, it would take me a significant time to stop because my truck is rated for 9,500 lbs.I run the living piss out of it and it has given me no problems at all/Hmm How did I get on the subject of my Toyota flatbed? OH, it\'s because I use the trailer brake setup I described which has been flawless. There are places that specialize in selling truck accesories only. From camper top and wheels to a variety of tow packages.Check them out. Good luck..

2006 Sienna Standard towing specs:

2WD or 4WD: Max Tongue Weight: 200 lbs
Max trailer and cargo weight: 2,000 lbs;
(over 1,000 lbs requires trailer brakes)

Max trailer and cargo weight: 3,500 lbs WITH the factory tow package

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I am a Tech Services representative for CURT Mfg. which manufactures an entire line of electrical harnesses. I would recommend our 55244 if your vehicle was equipped with a tow package from the factory. However, if it did not you would need to manually splice in a powered 3-2 converter into the back of your taillights. CURT Mfg's part number is 56146, although you would be able to find it's equivalent at many different auto parts stores around the country.

You have got 7 pin trailer connector that was included in the optional trailer tow package. This trailer tow package also includes an electric trailer brake wiring provision that terminates at a connector located on top of the large body harness connection under the instrument panel to the left of the break pedal, as well as an electric trailer brake pigtail harness and an instruction card that are stored in the glove box when the vehicle is shipped from the factory. You will need to add an electric brake controller of your choice that will plug-in to the harness and that will also give you power on your auxiliary circuit.

You likely need diode isolators on the turn signal wiring on the trailer, or on vehicle side connector. Your local auto parts store should have what you need, and show you how to install them.

It looks like there could be a service bulletin to fix this.

TO: ALL TOYOTA DEALER PRINCIPALS,
SERVICE MANAGERS, PARTS MANAGERS
SUBJECT: SPECIAL SERVICE CAMPAIGN 10H
(2000 TUNDRA AND 1999 - 2000 TACOMA TRAILER TOWING WIRE HARNESS
CONVERTER REPLACEMENT)
Toyota will initiate a Special Service Campaign to replace the Toyota Trailer Towing Wire Harness
Converter (converter) on certain 2000 model year Tundra and 1999 - 2000 model year Tacoma
vehicles equipped with a genuine Toyota Trailer Towing Hitch or Bumper Hitch. This accessory
is included in the Towing Hitch Kit installed at ports (PIO) and by dealers (***); it is also sold by
dealers as an over-the-counter or service part.
An electrical short or open circuit can cause a fault in the genuine Toyota Trailer Towing Wire Harness
Converter (converter). This can cause a failure of the converter, and if a trailer is being towed at the time,
non-operation of the trailer lights. In limited cases, the converter housing could become heat-deformed.
In the case of the Tundra, the circuitry utilized in the converter was inadequate to properly manage
vehicle and/or trailer-side voltage spikes. If the converter is exposed to a voltage spike it may cause an
electrical short or open circuit within the converter.
As for the Tacoma, due to deficient waterproofing and improper installation location of the converter,
which is mounted in the lower portion of the taillight cavity of the vehicle, an electrical short circuit will
occur if water enters the converter housing.
The following vital information is provided to inform you and your staff of the campaign notification
schedule and your degree of involvement.
1. Owner Notification Letter Mailing Date
The owner notification will be conducted in two phases:
• The first phase will be launched in late August and involve vehicles equipped with port
installed (PIO) genuine Toyota Towing Hitch Kits.
• The remaining vehicle owners, whose vehicles may be equipped with a dealer installed (***)
genuine Toyota Trailer Towing Wire Harness Converter, will be notified in the second phase
to be launched in early September.
We have attached copies of the owner notification letters for your reference.
If you are contacted by an owner of an involved vehicle, who has not yet received a notification,
please verify eligibility through TDN or TIS, inspect the vehicle to assure it is equipped with the
affected part, and perform repairs as outlined in the attached Technical Instructions.

usually if you look under the rear bumper or behind one of the taillights you should already have the harness there for the setup just buy the plug and hook up the wires by going with same color

Sounds to me to be a groung issue. Have you tried to hook an external ground between the truck and trailer? If you got everything at the plug thats not the problem.

I recommend that you tighten the ground wire screw for starters. since the vehicle is ten years old corrosion may be the culprit.