Re: strange trailer wiring with 2002 Quad Cab w/factory 7-pin connector.

From: jon@dakota-truck.net
Date: Thu Nov 03 2005 - 10:28:30 EST


"Miles D. Oliver" <moliver@mmoliver.org> wrote:
: I have a 16 foot Kaufman auto trailer with electric brakes. It came with
: a 6 pin wiring connector and I purchased a 7 pin connector and wired it
: according to the diagram on the cap of the factory 7 pin connector under
: the bumper of the Dakota.

  
 
   Just to clarify, what you did is to cut off the 6 pin connector from
the trailer and then replace it with a 7 pin?

: I feel that the trailer end 7 pin female connector is wired properly
: because I can plug it into my brother-in-laws Chevy Pickup with a 7-pin
: connector and all lights, including the running lights function properly.

: This is an odd problem that I can't seem to find a solution to, The
: running lights operate EXACTLY OPPOSITE of what they are supposed to do.

: Can anybody give me a clue as to where to go with this?

   I would tend to agree with your assumption that the trailer and your
female 7 pin connector are OK since they work as intended on the Chevy.
What I would do is to focus on the Dakota, since it sounds like that is
where the problem lies. My next step would be to put a multimeter on
the 7 pin male plug on the truck, specifically between the ground pin
and the running/tail light pin. Check it with the lights off, and then
check it with the lights on. If there is a voltage on that pin when the
lights are off, and vise versa, no voltage when the lights are on, that
would definitely confirm that the truck is at fault.

    Assuming that this is indeed the case, if you have any warranty left
and don't feel like playing with it, you could have the dealer check it
out, or otherwise you'll need to figure out where that wire goes and
trace it all the way back to the headlight switch, if necessary. I
don't know exactly where this wire draws its power from, but if it is
from the PDC under the hood, it could be as simple as Dodge connecting
the terminal to the NC contact instead of the NO contact of a relay socket.

   If you would like a quick and dirty way to get it working, you can use
a 5 pin automotive relay (SPDT); run a source of 12v for the trailer lights
to pin 30, cut the running light wire running from the truck to the trailer
plug, and hook the plug side to pin 87a, the truck side of the running light
wire to pin 85, and run pin 86 to ground. (Pin 87 doesn't get connected to
anything.) This will direct voltage from your 12v source to the trailer
lights when there is no voltage on the trigger wire (the original running
light wire), and will cause no voltage to go to the running lights when
there is a voltage on this trigger wire. This is definitely the automotive
equivalent of treating the symptoms instead of the disease, and you would
be better off to find the root of the problem, but I thought I would just
throw this "solution" out there in case you didn't have time to trace the
wiring at the moment and need to get it working *right now*. :-)

   Good luck with it! Let us know how it works out, and of course if you
have any other questions/problems I'd be glad to help if I can!

-- 
                                          -Jon-

.-- Jon Steiger ---- jon@dakota-truck.net or jon@jonsteiger.com --. | 67 Coronet, 70 Cuda, 90 Dakota 'vert, 92 Ram 4x4, 96 Dakota | | 96 Intruder 1400, 96 Kolb FireFly, 99 Cherokee, 01 Ram 3500 CTD | `------------------------------------ http://www.jonsteiger.com --'



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