[A/S] Dodge Ram 7 Pin Connector

["Harvey Barlow" <harveybarlow@xxxxxxxxxxxxxxxx>]

Jim,

I went out and braved an icy north wind to check out the seven pin connector
on the back of my truck this morning.  Bad news, at least for me, I was
correct.  The trailer charging line is always hot.  It is not switched.  If
I should discharge my trailer batteries with the trailer and truck
connected, it appears that I could also discharge the truck's starting
batteries.  If I get motivated one of these days I'll study installing an
ignition-switched relay to interrupt that circuit and isolate the truck's
batteries from the trailer.

With my truck sitting idle, ignition switch and lights off, pin number 4 is
continuously hot.  Pin # 4 was the only pin that was hot.  I made a crude
sketch to ensure we are talking about the same pins.
        DODGE RAM TRAILER CONNECTOR  (industry standard)
                        ________
                        |                 |
                 ___|                 |___
                 |      3 /           \  4     |
                 |               7              |
                 |   5  |       O      |  6   |
                 |                               |
                 |    1   \            /  2    |
                 |______________|


    Pin #        Function
    1                Ground
    2                Trailer Brake
    3                Stop Light
    4                Fused B+ (always hot)
    5                Left turn signal
    6                Right turn signal
    7                Back-up lamps

The number four pin is actually more at the 2 o'clock position than my
sketch indicates but I couldn't think of any way to illustrate the pins
other than using slash and back slash keys.

Is your Dodge pin # 4 switched?  I found a good Dodge Ram discussion site
through the TDR forum.  Dave Fritz's site at http://www.dodgeram.com
discussed the trailer connector and showed this diagram.  He referred to
Dodge TSB (technical service bulletin) 08-33-96 which indicated that all
Dodge's are wired in the same manner.  I don't understand why they would
have done that.  It would only cost the manufacturer another dollar or two
per unit to provide for that circuit to be switched by the ignition key like
my former Ford was.

Someone else may be able to use the sketch for wiring or checking wiring on
a newly purchased older unit because tow vehicle seven pin connectors and
trailer male plugs are all wired to RV industry standards now.

Harvey