Getting ready to tackle the trailer plug wiring on the truck tomorrow morning and was wondering if someone could school me on brake controllers.

Truck has installed a 4 pin round, 6 pin round, 7 pin round but the po's wiring is hacked and spliced to heck. No problem I say to myself while peeling back an entire roll of electric tape lol

My trailer uses the 6 pin and, of course it's not hooked up. I would leave the rest of the connectors unhooked if the one I needed was working but of course now I need to get the one going and why not the rest of them.

What's the factory wiring? There's a big plug looking thing under the bumper that the tail lights split off of and has 4 pin flat coming right out of the side. Is this the factory tow package set up? Just out of curiosity, the wiring will be no problem I think pending it's good to the back.

There is a brake controller set up on the under dash that has a metal line tapped into the master cylinder. Looks pretty old school and I have 0 experience with them so how does this setup work? Is there a way to test these these for proper operation before I go hooking the wiring back to it I'd like to be sure it's operational.

 

Sound like an old school controller. The metal line was teed into the brake line, when the brake pedal was pushed, it also activated the controller threw this line. The contoler probably has a **** on it that moves when the brake pedal is applied. You could also activate the trailer brakes by moving the **** manually. On second thaught some just had a push bar on them that you would use to manually activate them. Two different manufacturers. I use a test light to get which wires are which. When the controler is activated you will have bothe the brake lights and trialer brake circut activated. If I recall right the blue wire from the controler is the trailer brake circut.

 

Those old school types are outlawed REMOVE IT... You could get an electronic Tekanosha for reasonable cost. Only thing would be the 12V charging wire for the trailer battery.... you may need to run one back from the front, best to fuse and relay that so it only works with the key on.

 

hope this helps out some the colors are USUALLY the same.but grab a test light to be safe

 

It's pretty fancy with a wood grained trimmed push bar lol. Sorry have to laugh it just looks like something right out of the 80's era. So yeah it's got the teed line into the brake line which as I understand when under pressure from pushing the brake activates the controller (pressure switch?) and sends power down the wire to the trailer plug in for trailer brakes? There is a fused blue wire, another fused one which I'm guessing is controller power, then brake and ground from what I gather. How does the sensitivity part work from the controller in how much brake it applies? Having never dealt with trailer brakes do they work like regular brakes or are they an on/off type deal?

So can I pigtail the controller into the 6 and 7 pin connectors no problem?

 

Oh yeah I'll be using the vom tomorrow to pin out all the wiring for sure but I'm not sure that the controller I got has a brake activation wire but it could I suppose. Still completely dummy lol.

 

Try this link for wiring diagrams.

Trailer Wiring Diagrams

My opinion, get rid of the 6 pin and 4 pin connections.
Wire the 7 pin connector in a standard configuration, then get a 7 pin to 6 pin and a 7 pin to 4 pin adapter.

Less wiring, less chances for shorts and with two adapter plugs you can be ready to hook up any trailer.

The tee with the 4 pin plug on it was an aftermarket adapter, and if it is in good condition you can get left, right and marker light connections out of it.
Battery power, brake power, ground and auxiliary power will have to be run from the front.

 

Agreed, that's how mine is set up, 7-pin connector with adapters, seems to work just fine so far. I'd have to disagree here, while it often works out alright this setup can burn up the main lights switch on the dash if truck is hooked up to a big trailer with lots of running lights. You need a relay to run lots of marker lights, and trucks that are not equipped with the tow package from the factory do not have a relay for their running lights, so you'll have to add one yourself. What I do when installing trailer wiring on a truck that originally had none, is use three aftermarket relays to power up the trailer lights, I feed the relays battery power through the trailer battery charge wire and I trigger them with one of those breakout harnesses you have now - this way the already weak factory running lights circuit and wiring don't get overloaded, and I can hook up a long 5th wheel or gooseneck and light it up like a Christmas tree if I wanted. Yes, and you may also wanna install a constant-duty relay for the auxiliary power to the trailer, this way your alternator will charge you trailer battery (if so equipped), but when ignition is off the truck and trailer's main power circuits get separated so trailer cannot drain down your truck's batteries.

 

You have to consider if the connector is the one I am thinking, it was an adapter that you unplug the stock wiring harness, plug the connector in and then plug the stock rear harness back into the adapter.

No, it don't do anything for upgrading the wiring size, but since no wires have to be cut, plug and play, it is a lot better than many trailer connector wiring attempts (hack jobs) I have seen.

If you consider cut the wires, twist them together and maybe tape them up with some masking or other tape, that adapter is a definite advantage.

Best option, run the wiring for the 7 pin trailer connection up to the engine compartment.
Use relays for tail/clearance light circuit with 12 gauge wire.
A relay on the turn signals may mess with your flasher, but that can be fixed by upgrading to an electronic flasher, 12 gauge wire.
12 gauge wire as a minimum for the trailer brake circuit.
Relay on the power supply circuit, 10 gauge wire.
Relay on the auxiliary circuit, 10 gauge wire
Ground wire to the battery negative, 10 gauge wire.

If you do that, you can eliminate the stock wiring for the tail lights and turn signals and power them from the trailer connector.
Be aware that the rear fuel tank sender wiring is also in that harness.
The reverse light wiring is also in that harness, and it makes a stop at the transmission reverse light switch.
On a 4x4, the transfer case 4x4 light switch wiring is also in that harness.
On my truck, the FSS wiring and front tank sender are also in that harness from their locations to the engine compartment.

Not sure, but I am also going to guess RABS trucks have additional wiring in that harness as well as the VSS wiring on 92 and newer trucks.

I actually use the battery power and auxiliary power circuit for fuel transfer tank pump connections, salt spreader power and work lights, so I used 6 gauge wire on mine as well as the ground wire with continous duty 100 amp relays.

When you do the install, get a good trailer connector that has a gasket on the spring loaded lid and don't forget to seal the back of the connector to keep water and salt out while driving on wet roads.
Otherwise you may open the connector only to find out the wires and connections have be eaten away since you last used it.
Also don't forget to protect the harness and secure it up inside the frame when you do the install.
Many auto parts stores have a plastic harness protector that is split down the side so you can slip the wiring in, does a nice job.
And good electrical tape, Scotch 33 or Scotch 88 may cost more, but it lasts a lot longer.

If you did the ultimate wiring install, soldered connections sealed with heat shrink tubing and liquid tape, Scotch Linerless Splicing tape, self vulcanizing rubber tape, is great.
Just keep it clean and stretch it as you apply it and it becomes a one piece rubber boot for the ultimate protection.
Cheap, no, but you will also never have to do the wiring again.

 

Dave, yes it is the same connector I'm talking about, it's quite nice setup really, but like you said it does nothing for upgrading the power-handling abilities of the circuits. What I di is combine that adapter with my own relays and wiring, it ends up working rather nicely. Haven't notice any issues with the flashers, probably cause the relay's control circuit inside draws so little power compared to a light bulb.

 

That small power draw makes some flashers think you have a blown bulb.
Many of the older style flashers used heat in a bi metal strip to flash, so not enough draw and they flash very slow or not at all.

Same flashers start flashing very fast when you add extra turn signal lights or the extra signal lights on a trailer.

If you used the relay with standard bulbs and the old style flasher, the current the relay used would not change the flash rate when you hooked up a trailer like it would if they were wired direct.

Since all my stock lights have been replaced with LED's, I had to go to an electronic flasher to make them flash at all.

 

LOL never heard they were outlawed but the newer all electric ones are much easier on trailer brakes and tires unless the hydraulic one is adjusted to your trailer and that was a pain and sometimes required a seperate resister. So a new one would be the way to go.

A lot of tire shops claim it is against the law to fix a flat on a split rim but it is because they are either afraid of them or don't know how.

 

Yes, that's just what I do - I retain all factory light bulbs, and I also retain the factory flasher, the relay current draw is so small compared to that of the bulbs that even tho it adds up to the truck's factory-setup draw the difference is negligible so the flasher don't even feel it, at least I haven't noticed any change in the rate of blinking. You ate entirely correct tho, upgrading to LEDs in the truck's own lights calls for an electronic flasher, additionally as one of my friends found out the E4OD PCM also does not like it when you use LEDs in the factory housings not sure exactly how she acted up but he lost the LED lights and replaced them all with regular lights and the problem went away immediately.

 

This makes me wander if you own a rig with the E40D and upgrade your headlights with relays would it make your tranny act different.

 

I'll have to add a relay it looks like as the lights are flashing fast. Easy enough and I have a few handy but was saving them for the electric lock wiring in the future. It works for now at least all lights on the trailer go like they should which is better then when I pulled it home yesterday with none.

Is there a different heavy duty flasher I can replace with or just go to a relay and be done with it?

Read somewhere that the new controllers are required to have a trailer break away system with battery back up for at least 15 min not sure how I fit into that category of if I get grandfather but I will say that for as many times as I've actually pulled a trailer with brakes (0) that it'll be nice to have if it ever comes up but there's no reason to run out and buy a new controller.


Good point out on the E40D I read they are finicky so would only imagine