Trailer wiring on 2006 Tacoma

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jaminn - 23 Apr 2006 22:23 GMT

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

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Bonehenge - 23 Apr 2006 22:38 GMT

>Am I missing something here? I know a little bit
>about wiring, but something isn't right.
>Jaminn aka Don Williams

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:
<http://www.championtrailers.com/TRAILER_RECEPTACLES.htm>

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

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jaminn - 23 Apr 2006 22:54 GMT

>>Am I missing something here? I know a little bit
>>about wiring, but something isn't right.
[quoted text clipped - 16 lines]
>I got mine at a local Advance Auto Parts store. Any Napa, Pep Boys,
>etc... will also have it.

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

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Bonehenge - 23 Apr 2006 23:11 GMT

> 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

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:

<http://www.etrailer.com/faq/wiring.asp>

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Bruce L. Bergman - 24 Apr 2006 00:07 GMT

>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
[quoted text clipped - 10 lines]
>about wiring, but something isn't right.
>Jaminn aka Don Williams

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.

--<< Bruce >>--

Signature

Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545
Spamtrapped address: Remove the python and the invalid, and use a net.

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jaminn - 24 Apr 2006 01:53 GMT

> 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.

> 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
[quoted text clipped - 4 lines]
>
> --<< Bruce >>--

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

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Bruce L. Bergman - 24 Apr 2006 04:07 GMT

>> Check the grounds on the trailer tail light assemblies to the steel
>>trailer chassis, and the ground wire from the trailer tongue steel,
[quoted text clipped - 11 lines]
>clean all that up and see if it helps. Could be part or all of the
>problem.

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.

http://www.truck-lite.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=100
01&storeId=10001&productId=23656&langId=-1

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.

--<< Bruce >>--

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Jeff Strickland - 25 Apr 2006 00:48 GMT

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

>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
[quoted text clipped - 10 lines]
> about wiring, but something isn't right.
> Jaminn aka Don Williams

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Jeff Strickland - 25 Apr 2006 00:59 GMT

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.

>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
[quoted text clipped - 10 lines]
> about wiring, but something isn't right.
> Jaminn aka Don Williams

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jaminn - 25 Apr 2006 02:38 GMT

>I finally got my pop-up in shape and was ready to wire the harness.
><snip>
>Jaminn aka Don Williams

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

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