Trailer wiring on 2006 Tacoma

I finally got my pop-up in shape and was ready to wire the harness. I very carefully followed the wiring diagram (I have the factory installed towing package, so the truck has the harness socket). But, something is screwy. As long as the truck lights are OFF, the trailer turn signals and brake lights seem to work. But if I turn the lights on, the brake lights don't seem to work, and the turn signals are acting strange. It's almost like there is not enough power, because it seems that if the lights are on, and I turn on the left signal, the right tail light will dim as the left signal flashes. Seems like I recall having to get a heavy duty flasher back in the day, but that was because the normal flasher would flash too fast when the trailer was hooked up. Am I missing something here? I know a little bit about wiring, but something isn't right. Jaminn aka Don Williams

Reply to
jaminn
Loading thread data ...

You've possibly miswired the connector.

The stock receptacle, which is trailer industry standard, worked great for me using either a store bought 4-pin converter or factory wired connectors that plug straight into the truck. No boosters, converters, etc... were required. I've towed 4-5 different trailers.

What kind of connector does your trailer have? For $8-10, you can get an adaptor that will adapt any standard wired trailer to what's on the truck. No need to rewire anything.

Here's an example:

I got mine at a local Advance Auto Parts store. Any Napa, Pep Boys, etc... will also have it.

Reply to
Bonehenge

Yeah, I figured I had wired the connector wrong initially. It's the 7 pin round type. The harness coming from the trailer had no connector on it, so I just wired the appropriate wires to the connector that I purchased from an auto parts store. I have checked, double checked, wired and re-wired. I think the wiring is correct. I keep seeing messages though about converters and adapters, etc. Makes me wonder if I can just wire directly to the socket. Jaminn aka Don Williams

Reply to
jaminn

Come to think of it, my 7 pin to other than 7 pin adaptors may have some sort of diode in them to prevent back feeds etc... My main trailer (Haulmark) has a flat, 4 pin connector, with the adaptor, I just plugged in and went.

In my experience, most of the stuff you described often pointed to a missing or poor ground.

See if this helps:

Reply to
Bonehenge

Check the grounds on the trailer tail light assemblies to the steel trailer chassis, and the ground wire from the trailer tongue steel, through the trailer connector to the truck body is continuous and solid - make sure there's a good ground path the whole way.

The trailer builders often try grounding the tail and marker light fixtures with a screw through the aluminum skin on the trailer, and that isn't always a low-resistance path. (Aluminum Oxide is an insulator.)

When there is a bad ground on a dual-filament lamp, you apply power to the stop lights and it can't go to ground, so it goes through the tail filament, to the other lamps, and finds it's way to ground.

If the whole trailer isn't grounded right the same thing happens, but it's not isolated to one fixture - all the lights act screwy.

-->--

Reply to
Bruce L. Bergman

The grounds are connected to the steel chassis, but it is rusty. I'll clean all that up and see if it helps. Could be part or all of the problem.

Thanks Jaminn aka Don Williams

Reply to
jaminn

The chassis can be rusty, as long as it's clean where the grounds attach. While you're at it, go get a 2-ounce squeeze tube or the half-pint can of Dielectric Lamp Base Grease - the one I use is Truck-Lite "NYK-77 Corrosion Preventative Compound", any good auto parts will carry it or can order it in for you quickly. Vaseline will work, but this stuff works better.

formatting link
UNPLUG THE POWER to the trailer lights. Take a plumber's 1/2" Copper Pipe fitting brush and clean up all the bulb bases and the trailer taillight lamp sockets and grease them.

They use Aluminum stampings for the Ground connectors in the lights, and they often get cruddy where the lamp base lugs hit the grounded lamp holder ring, or where the mounting screws get their ground from the body skin.

And if part of the problem turns out to be the trailer connector they make a special little cleaner brush for them, and you can use a dab of NYK-77 on the pins.

-->--

Reply to
Bruce L. Bergman

It sounds to me like you have a bad ground or no ground on the trailer.

Reply to
Jeff Strickland

BACK UP A MINUTE If you have the factory installed tow package, and it includes the flat

4-pin connector at the bumper, then you need a flat 4-pin connector on the trailer.

The trailer uses the SAME lamps for turn signals and brake lights, and another for running lights -- that is, the bulb has two filiments, the brake and turn signal is one filiment, the running lights are the other. Your truck has a filiment for brakes and another for running lights, and a completely separate bulb for turn signals. You should be able to see the conflict here, you have two different lighting systems and are wanting to run them from the same control.

The truck MUST have a converter built in that is essentially a diode pack that blocks voltage from flowing back from the trailer and into the truck, causing lights to flash that should be on steady. Since you have the factory installed Trailer Option, then you should already have the converter device, and your troubles are centered in the trailer.

If you THINK you have the factory trailer option but you really do not, then your lights will not work right until you get the proper converter and install it. The one I installed was very easy, and I fit into the fender, justj forward of the left tail light assembly. All of the wires connected very easily, and only one wire has to go to the right side to pick up the right turn signal. The converter has a flat 4-pin pigtail that you mount near the hitch, I set mine so it comes out beside the license plate.

Reply to
Jeff Strickland

Problem solved. Thanks for all the input, by the way. This afternoon I checked all the grounds, even took one loose that was on a rusty part and cleaned it, drilled a new hole and re-attached it. Then, I applied 12 volts to each wire to make sure all the bulbs worked pn the trailer as they should. All were fine. Hooked up the cable from the truck to the camper and the lights still didn't work. So, I got to looking elsewhere. I noticed on the cover of the truck connector that it showed the location of the wires. I noticed right away that the ground on the cable connector wasn't where the ground was on the truck connector. So, it appears that I was confused by the pin out provided with the cable connector (it is a 7 pin, round connector). Once I figured out where the ground was, the rest of the connectors just fell into place. All work fine now. I'm ready for next month when I will be pulling the camper 1000 miles from GA to TX. Jaminn aka Don Williams

Reply to
jaminn

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.