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Ram Trailer Connector Wiring Hints

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Brake Controllers

From TSB 08-33-96

1  Z13 12BK GROUND
3  L76 12BK/OR TAIL LIGHT (Trailer Tow Relay in PDC)
4  A6 12RD/TN* FUSED B(+)   (40A, Always Hot, F8 in PDC)
FIGURE 1:   7-Terminal Trailer Tow Connector
* some trucks have orange or red/orange wires for B+

From a 1995 issue of the Star Center News:


Both the factory installed trailer tow harness and the Mopar, Parts trailer tow harness do not require the trailer tow harness overlay kit. The necessary relay is in the PDC when the harness is installed at the factory, and the Mopar Parts trailer tow harness has the relay built into the harness. The overlay kit is erroneously listed in the 1994 New Dodge Ram Cummins Turbo Diesel Owners Manual(Publication No. 81-326- 9422), the 1995 Dodge Ram Pickup Truck Owners Manual (Publication No. 81-326- 9522) and also on an addendum card (81-016-9422).

Subject:       more TSB gems-towing lights:again
From:          bob bergevin <>

-- This gem will assist anyone who tows many kind of trailer and does NOT have the factory supplied as-built towing equipment option OR the CC tow harness supplied aftermarket.  As I have said before, and others have supported, you are courting with a fire or at the least a destruction of your headlight switch if you continue to tow, with your lights on, without the CC harness installed as directed.

If you don't have the harness, spend the $ and get it!  look at or for prices-they seem to be close to the dealer costs.  the part numbers are:

for a 4 wire harness (Left turn, right turn, parking and ground) the part # is  82401264  Outside of Europe the turn signals are interrupted brake lights on that side thus-4.  This for light duty trailers, boats, snowmobiles, bikes, etc.

for a 7 wire harness (ground, electric brake output, clearance lights [parking/running lights], B+ [12 v power to the trailer for jacks, battery, inside lights etc], left turn, right turn, backup lights), the part number for all '94's and all 94-97 Cab/chassis models is 82400961.

For a 7 terminal harness for all 95-97 EXCEPT Cab/chassis models the part number is 82401265.

The part number MAY have changed so make sure you tell what you want and make sure the relay for the parking/clearance lights is with it! It is important that it be installed as the directions say as the TSB sez "...the current carrying capacity of the headlamp switch is limited to the lamps used by the vehicle only"

Tow both a 4 and 7 pin trailer?  a 7 to 4 adapter is part # 56019823 and a 7 to 6 adapter is # 82401217.  Don't forget the heavy duty flasher if you didn't have the  original equipment towing group.  CC is # 02932877.

Subject:       Re: 7-Pin Connector Wiring
From:          Drdonnelly <>

My 97 Ram did not have the factory trailer package.  I wired the 7-blade connector myself, and soldered all connections before taping and sealing with black RTV.  My truck had the front part of the harness and the connectors in the fuse box under the hood [power distribution center, PDC].  The 4 blade connector under the dash was there too.  Of these 4 wires, the red/tan is "hot", tan/white is the brake sensor, black is ground, and blue is for electric brakes.

At C128, 129 behind the front inner wheelhouse, attached to the bottom front of the cab behind the tire, you will find that the harness going from there to the rear of the truck is missing two wires that are needed for the trailer connector at the rear bumper.  These wires are for the trailer running lights (black/orange) and trailer brakes (light blue).  I ran 10 gauge wires to the rear for these functions, as I prefer heavier wire than OEM anyway.  OEM used to be 14 gauge in 1995 and later they upgraded to 12 gauge.  By tapping into the cab end of the connectors, you can access the power leads that you need from the front harness which has these functions even in non-trailer-towing trucks.

At the rear end, I tapped into the brown/pink lead for right turn, and dark green/red for left turn.  Violet/black is for backup lamps.

From the PDC connection for the 120 amp fuse, I ran 8 gauge for the B+ (battery positive lead) that is used to charge the trailer battery, and another 8 gauge for a ground from the battery terminal.  This setup with 8 gauge wires allows charging the trailer battery "on the road" much quicker than the stock 12 gauge wires would.

In summary, you now have 7 wires:  right turn, left turn, backup, 10 ga. running lights, 8 ga. B+, 8 ga. ground, and 10 ga. trailer brakes.

This arrangement is heavier duty than stock, and was worth the effort for me. I also used a DrawTite "Ultra Frame" hitch rated at 750 lb tongue weight and 7500 lb trailer weight in weight carrying mode, vs. stock 500/5000.  The Draw Tite uses 9/16" bolts, four per side, vs. stock metric which are about 7/16" and three per side.    Joe

Subject:       Re: 7-Pin Connector Wiring
From:          Jeff Trithart <>

The factory Mopar wiring package just plugs in the trucks harness at the back of the truck.  The black and blue wires get fed up alongside the frame to the engine compartment.  The black wire gets hooked into your power distribution center beside the battery.  The blue wire is for your brake controller.  My 97 comes with a brake controller plug under the dash that accepts an aftermarket brake controller that is wired for my truck.  When using this controller, there is no wire cutting under the dash to hook it up.  The blue wire can be fished down into the factory harness at the factory plug.  Look behind the drivers front tire, up in the rear of the fender well by the drivers door and you should see to harness connectors.

If your truck did not come with the tow package, one of these connectors (if i'm not mistaken, the bigger one) will have the same color blue wire going in but not coming out the other side.  This is your brake wire from the controller. Unplug the connector and pull out the port plug where the blue wire should be coming out of.  Install the correct size spade connector to the blue wire coming from the rear of the truck and plug it into the connector.  After the connector is plugged back together, cut a slice in the port plug you removed (it's foam) and re-insert it into the connector.  You now have a factory looking tow package wiring harness.      jeff trithart

Subject:       Re: [RAM] 7-Pin Connector Wiring

From:          HUES11 <>

There is a very nice aftermarket harness from a company called Hoppy-Lite. They use the factory weather tight connectors and plug directly into the tail/stop lamp factory harness. They come with wire loom around the wires and are completely sealed. The Hoppy Lite harness will have a four way connector four the lights mentioned above and you can buy a Hoppy Lite connector that goes from there. The connectors are available in four way six way and seven way just like the factory connector.

Subject:       trailer towing wiring
From:          bob bergevin <>

-- Beware all those who crawl under and lay out wiring for their trailers in their RAMs...  The CC trailer harness is available as an aftermarket part and SHOULD be used as it contains a relay for the clearance lights of the towed vehicle that does not go through the headlight switch.  The switch CAN NOT take the current flowing to feed some 6 or more clearance lights and it will "fry" the switch.  I have seen it several times!  The trailer tow option includes the relay tripped from the headlight switch, and the aftermarket CC harness is installed exactly the same way.  (retail some $90 +/-)  The harness also includes a fuse for circuits A6 the battery feed, and L76 the feed from the relay to the trailer parking lights, license light, and side/front/rear marker lights.  Don't tow without the relay or a similar setup or I promise you  you will buy yourself a new headlight switch eventually!!     Bob Bergevin

Subject:       Re: trailer towing wiring
From: (Paul R. Haller)

One thing CC didn't put in the trailer tow package which ,IMHO, is a necessity is a relay on the charge line. If your batteries are in a discharged state on the trailer and you hook up they could pull down the battery in your truck preventing you from starting your tow vehicle. I put in a heavy duty relay in the charge line and used the cigar lighter as a feed to energize the relay when the ignition switch is in the on position.

A relay in the back up light circuit would also be useful for replacing those pathetic stock back up lights on the truck. This relay would also solve burning up your back up light switch when additional lights are added to your trailer for backing up.

Subject:       Trailer Wiring Harness
From:          "Steve C. Huminski" <>

   I just had a Glasstite fiberglass cap installed on my baby, and the guys wired up the third light in the cap to the trailer harness, which, on my 1997 5.2 Auto CC SB, was in the engine compartment, right under the power brake booster and master cylinder, just hanging there.  Try looking there, its a small black plastic connector.  Good luck.     Stephen C. Huminski

Subject:       Re: Trailer Wiring Harness
From:          Bill A <>

The service manual labels this a center stop lamp test connector. Glad you could find a better use for it. its a lot simpler than trying to tap into the trailer harness, if they did the high mount lamp would blink with the turn signals. The majority of caps I've come across use a jumper from the existing stop lamp, which IMO looks kinda blue-light special-ish.     Bill A

Subject:       Re: 7-Pin Connector Wiring
From:          Drdonnelly <>

> How'd you fit all those fat wires into the plug body?  Is there a trick or a
> bigger plug to fit them all?

some or all of the fat wires can fit into the 7 blade connector, but it is hard to get that much wire under the screws!  Well, even if you have to clip off a few strands, or use a short pigtail lead of smaller gauge wire, you will gain most of the benefit from less voltage drop, etc.  That is why I used the factory harness which is 12 ga vs. 10 ga as I posted earlier, in the front of the truck.  I still gained some on the run to the rear of the truck, and was not as worried since the new trucks use 12 gauge vs. the 14 gauge used in 95--marginal, IMHO.

>  I installed the hitch  with fine-thread grade 8 bolts just to be sure,
> fiber locking nuts, and  dinged the threads to assure no amount of
> bouncing around would loosen them.

If the bolts are properly torqued, and I use good moly wheel bearing grease for smooth torque readings, the bolt holds because it is stretched a bit.  If they work loose any at all--even the little bit you could get with crimped threads, etc, the hitch may fail.  These bolts are designed to clamp the hitch to the frame.  As such, they are not designed to resist in shear mode, and they will shear if loosened.  The flywheel is another such example where clamping load is what holds the parts together--crankshaft and flywheel.  Bolt shear strength is not the intention, and that is why I remove all the frame wax before tightening the hitch to the frame.  The wax says "slide here" and the bolts then can shear.    Joe

Subject:       Fifthwheel wiring connector
From:          Bill A <>

> According to the Book there is supposed to be an extra connector, midway
> on the wiring going back to the trailer hitch. Two mechanics and the
> service manager couldn't find it. (Truck on lift)  Who knows where the
> connector lurks?

Its stuffed into the wiring loom inside the frame, alongside the fuel tank. Look inside the bed, there's a nylon knockout in front of the wheelhousing where the wires are supposed to come out. Remove the knockout and it'll be a little easier to see.     Bill A

Subject:   Re: Brake Controllers
From:      Don Bowen <>

At 10:13 AM 5/18/98 -0600, you wrote:
> In the market to buy a new trailer brake controller. Any suggestions?

When I asked this same question last month to several lists, the overwhelming recommendations were for the Tekonsha  voyager models.  An antique tractor list I am on has several people who regularly pull heavy loads to shows all over the country and most recommend the Tekonsha.

Some comments below.  Names removed because I have not asked anyone's

The number of braking axles you have will affect your choice.  For 1 or 2 axles, I heartily recommend the Tekonsha Voyager.  It has a light which is green to indicate a good connection to the trailer brakes, and the light turns red or yellow to indicate braking.  This one is easy to adjust to the load you are hauling.  This is important as the braking required with several thousand pounds on a trailer will lock up the tires on an empty trailer.


I think we did have a thread on this earlier this year.  I have had good luck with my Tekonsha Commander.  Fully electronic, some nice features for compensating for empty or full trailers once you have it calibrated to your trailer....  I think I paid about $80.00 at CarQuest.


I feel the two "voyager" models offer the best features in the Tekonsha line. It has fully adjustable braking intensity and leveling features, and is very easy to "dial in" for the braking you want.  From what I read in the catalogs, the 9030 (2 & 4 brakes) and 9035 (6 & 8 brakes) are fully capable controllers at a price that is quite a bit less than the other models.  For a 4 brake system (tandem axles) my supplier list the following regular prices

2030            $75.86
9010            $81.95
9030            $66.92
9055            $88.02

Both the 9010 and 9030 are billed as "Compatible with ABS brake systems", the others do not mention that.

I've run several rigs with the 9030, including my own, and they seem to work just fine.


I have had good luck with the Tekonsha Voyager.  Using the same unit for the last 6 years with no problem.  Will probably go with the new Sentinal model (Tekonsha) if this one gives up the ghost.  They have a website if you need more info.    Don Bowen   

From:      "Sean Hartling" <>
Subject:  Re:  Brake Controller Info Please

> I have access to a trailer that is equipped with electric brakes and says that the
> tow vehicle must be equipped with a brake controller.  I have the tow group
> on my truck which came with a wiring harness for a brake controller.  I'm not
> familiar with how these things work or how to install or use it. Is there
> a web site or book I can refer to to learn about this technology?

Your user manual indicates where you have to plug the brake controller into the truck.  It's a 4 prong connector under the dash.  I have to do it on mine for the trailer I'm pulling and I looked it up in the user manual that comes with the truck.  You don't have to splice into the brake wire either, it says that there is a wire connector for the brakes.  I haven't found this wire yet but I found the 4 prong that goes to the wiring harness to the back of the truck.  I have a 97 1500, so there shouldn't be much of a difference. The 4 prong on mine is located behind the emergency brake up under the dash a little ways.     sean

From:      "Ralph W. Frank Jr." <>

Go to this web site it should help you with electric brake controllers.