Another trailer wiring question

[chin_k]

There are a few thread related to the trailer wiring, and since I see a few of you are here recently, I think it maybe a good time for me to take advantage of, and get mine straightened out.

Here are some of the related threads:
setting up for a tandem trailer -
Running lights don't work
Updates to our 1993 Concourse - Project Thread

I looked at mine, and there is this wire loom that come down from the coach, and it split off to 3 grounds that attached to the frame rail, 1 loom that looks like the gray water tank level sensor wiring, and one that goes further down the line. That loom that goes down the line is further splits into tthe two Ford's "schnozzle" connectors, the 4 pins flat trailer connector, and another loom that goes back to the side of the waste tank.

My understanding is there are two wires from the 3-wire Ford connector that go all the way to the driver area for fusing, while the 4 wire Ford connector connects with the 4 pins flat trailer connector. My question is what is the loom that goes back and disappeared into the side of the tanks along the frame rail? Another question is if I want to add a 7 pins connector, what is the best way for me to tap into the 3 wires in the Ford connector?

[chin_k]

Code: Select all

  ||
  | + --
  | + -- three ground lugs
  | + --
  | | 
  | + = two wire tank level sensor
  | |
  | |
  | + = 4 wire Ford connector
  | + = 3 wire Ford connector
  | + = 4 pins flat trailer connector
  + = mystery wire loom....
 

[Blue~Go]

Okay, let's see if we're on the same page here.

1) The ground lugs are just that: Grounding points for internal coach chassis grounds (negatives). There is another on the passenger side in roughly the same place. That's pure Chinook.

2) Small wires that screw "into" the sides of the tanks. These are the tank level monitor sensors. IIRC there are four on each tank (cause the monitor shows various levels). Pure Chinook.

3) The two Ford trailer wire "schnozzles." These *were* pure Ford. Brown one has the basic four trailer wires (brown/green/yellow/white, which are tail brake turn and ground). Black one has the other three (back-up, brake, 12 volt supply).

Chinook decided to use these for the coach tail and marker lights. Surprise! That''s why some of them not only go to the four-way flat trailer connector (plus a bonus wire from the other schnozzle for the back-up lights), but ALSO go up into the floor in a glob of sealant (just west of the tire locker outside wall) to join up with that system.

I found this because I needed to make my trailer wiring 5-way (but I always use a 7-way physical connector because I dislike the functionality of the other styles). I ALSO was reminded of it when I towed a trailer with something like 28 incandescent tail/marker lights. Blew the fuse because Chinook had only piggy-backed on the 12 or so tail/marker lights of the coach (via like three up/back runs of skinny wire no less). It's perfectly fine if you have LED trailer lights (or not too many incandescent), but a fun time to track down at 10 p.m. in the truck side of a rest area

Does that help? I have previously posted copies of the Ford sketches showing the schnozzles.

BG

[Roly]

Interesting that trailer wiring comes up now.

Months ago I was involved in the "Setting up for a tandem trailer" thread, harvested info from Blue, and did lots of work to get a 7-pin setup. I miswired something and never ended up buying a cargo trailer because the lights only partially worked. Under a schedule gun, I made my final moving household trip with a Uhaul truck instead of the planned Chinook and trailer, and have yet to straighten out the wiring problem. It cannot be impossible, like my solar problem......

I still would like to be able to pull a cargo trailer or boat. I will watch here what you learn, Chin, and contribute what I can.

Roly

[chin_k]

Okay, let's see if we're on the same page here.
...
3) The two Ford trailer wire "schnozzles." These *were* pure Ford. Brown one has the basic four trailer wires (brown/green/yellow/white, which are tail brake turn and ground). Black one has the other three (back-up, brake, 12 volt supply).

Chinook decided to use these for the coach tail and marker lights. Surprise! That''s why some of them not only go to the four-way flat trailer connector (plus a bonus wire from the other schnozzle for the back-up lights), but ALSO go up into the floor in a glob of sealant (just west of the tire locker outside wall) to join up with that system.
....
BG

Blue:
You can find the diagrams you and Roly posted in the threads I listed above. So are you saying the mystery loom is the wire that goes up to the floor, and ended in the driver area with the fuses? How about the bundle where the loom come down into the bottom? I assume that is where the two wires that goes to the driver area for fusing for the marker light... It will be very helpful if I can get my hand on the wire color and how the wiring is routed. I am thinking to unwrap the electrical tape around the looms and start to decipher it myself, but being lazy, I want to get some advice from the various sages we have on the forum first. (To be honest, the dirt started to fall on my face, and I give up after getting a taste of some of the dirt. I did wear eye protection, but maybe I need a full face shield.)

One particular thing that I want to address is how to get rid of the back-and-forth wiring.... I know most newer trailers have LED lamps, so this is not really an issue, but if the wiring is just to put a fuse holder near the driver side, is it possible to relocate the fuse in the rear and by-pass most of the back-and-forth wiring? ( Eventually, I want to add a backup camera and I may be able to use the abandoned wire for either as a signal wire, or as fish-tape to pull new wiring thru...)

[chin_k]

I got a Curt 57102 finally after about two years of putting this project off. I installed it over the course of past few day, and it is mostly working. I will get to that in a moment.

I unwrapped the bundle of wiring behind the two schnozzles, and found that Chinook used the brown one for the four-way flat trailer adapter, like Blue said. There are 3 wires on the black schnozzle, and Chinook used the backup wire for something that I do not know. Should have left it disconnected to see if the backup wire go to the two white backup light, but I already crimped the connection.

Anyway, the Curt 57102 has a backup buzzer, and that is why I brought it. It has an extra white 8 AWG ground that I need to connect to the frame, and I installed it right next to the three ground lugs on the frame. Took me a very long time to drill thru the thick steel plate, and I wish I were less stubborn and just use one of the existing lugs instead. After I connected the Black-with-light-green wire from the black schnozzle to backup wire for the 7-way connector, I tested the buzzer by backing up, and it worked. Gave off a loud beeps with red LED (I wish they are white...), made it sounds like a cargo truck.

I attached the accessory wire (Orange one from the black Schnozzle), and it has 12V when the key is in the ignition with ACC.

However, I finished the braking wiring (dark blue), but was not able to find any voltage on it. I hope it is due to a blown fuse or something simple, otherwise, I would hate to have to spent all that time, and end up with a partial install. I am going to do a quick search and see if I can figure out why... do I need to put a relay on the Chinook for the brake to work? Or since it came with the towing package, I assume the brake wire should be functional.

[chin_k]

I checked the fuse box near the near the headlight, and the fuse that seems to related to this is the #20, Electric Brake Controller (20A). The fuse is fine. So my next step is to look for the brake controller? Does the Chinook come with one, or it needs to be installed by the owner? I am clueless on this.

[Blue~Go]

I unwrapped the bundle of wiring behind the two schnozzles, and found that Chinook used the brown one for the four-way flat trailer adapter, like Blue said. There are 3 wires on the black schnozzle, and Chinook used the backup wire for something that I do not know.

It's been almost 8 years since I wired mine, but I believe you have that right. Because basically, Chinook used Ford's trailer wire provisions (the schnozzles) for the RV's own taillights (bit tacky of them if you ask me).

So the brown schnozzle has the 4 wires that are in the most basic (4 way flat) trailer connection. Those are the typical brown, yellow, green, and white. Brown is taillights, yellow is left turn signal/stop, green is right turn signal/stop, and white is ground. Notice that there are no back-up (reverse) lights? Well the black schnozzle has the "extra" wires that you would have in a 7-way trailer connector. So that's three more which are black/light green for reverse light signal (not that trailers usually have reverse lights, but this is typically used to tell the brakes on a surge brake trailer that "hey, I'm backing up, brakes should not come on!); orange for power (minimal, tons of voltage drop); and dark blue for brake controller (for electric or electric-over-hydraulic trailer brakes).

So, Chinook used the wires from the brown schnozzle, and then took the just back-up (reverse) signal light from the second schnozzle to power the reverse lights on the Chinook. They didn't need or use the power or brake controller wires. This whole trailer wire repurposing scheme works (mostly) because the Chinook has red turn and tail/stop lamps. (I don't know how they did it on the Chinooks that had the amber turn signals in the rears - maybe some sort of reverse converter that you'd typically use on a two vehicle with amber towing a trailer without?)

Anyway, the Curt 57102 has a backup buzzer,... I connected the Black-with-light-green wire from the black schnozzle to backup wire for the 7-way connector, I tested the buzzer by backing up, and it worked. Gave off a loud beeps

That makes sense, as that black/light-green is the backup light wire.

However, I finished the braking wiring (dark blue), but was not able to find any voltage on it. I hope it is due to a blown fuse or something simple, otherwise, I would hate to have to spent all that time, and end up with a partial install. I am going to do a quick search and see if I can figure out why... do I need to put a relay on the Chinook for the brake to work? Or since it came with the towing package, I assume the brake wire should be functional.

This is only used when you have a brake controller mounted in the cab (eg Prodigy P3), and the matching brakes to control on your trailer (electric brakes or electric-over-hydraulic brakes - the latter commonly used on boat trailers). Otherwise it has nothing to activate it and nothing to apply either. With surge brakes (many boat trailers, U-haul rental trailers, etc.) you don't need or use that wire. (But you might use the black/light-green wire if there is a solenoid on the trailer coupler to lock out the brakes when you back up - typically a 5-way flat connector.)

So, I think it's normal that this not be "working" since you don't have a brake controller in the cab, nor the brakes that take that kind of control on your trailer (because if you did, you would know). If you do want to tow a trailer that has electrically controlled brakes, then you'd mount a brake controller in the cab (Prodigy P3 or other) and through that dark blue wire (and a 7-way trailer connector) it would control the electric brakes on the trailer (this type of controller typically works proportionately on its own, or you can pinch levers together and manually apply the trailer brakes).

Many (most?) states require trailer brakes of some kind of trailers weighing over around 3,000#. If they are surge brakes then you still wouldn't use the dark blue wire/brake controller (but very well might use a 5-flat to include the black/light-green wire).

***************
One thing to note is that because Chinook used Ford's trailer wiring for their own tail and marker lights (plus did so with long skinny wires going up and back), you can easily have a problem if you are towing a trailer with many incandescent lights.

I had towed a boat many times with no issue. But it just so happened that I had converted the boat trailer's tail/turn/stop lights to LED before I started towing with the Chinook so all was fine. Then I hooked up a "Haulmark" type cargo trailer (with twenty jillion incandescent marker lights, plus taillights) and next thing you know my friend behind me was telling me I had no rear/marker lights on the Chinook or trailer. Just four short hours of lying in the dirt in a rest area at night and I had that one figured out

There would be a couple of solutions: You could do a better job with the Chinook side of that wiring. I think the problem is mostly in the "marker lights" wire that goes around the horn three times and is super skinny. Larger wire, or perhaps put that fuse aft. The other way to solve for it came about naturally in my case: I changed the cargo trailer lights to LED lights, and many/most trailers now have LED lights. Problem solved by reduced draw and they are an upgrade on trailers anyway (fewer corroding connections, longer "bulb" life).

[chin_k]

Thanx, Blue. I did some reading and digging on the net myself last night, and found that unless I have a brake controller in the cab, there is no signal or voltage on the brake wire. I did not expect that, but it makes sense, particularly after your explanation. I am all set for towing, and got a 2" ball the other day when I rented a car dolly from U-Haul. As you know, it use surge brake, so all I need is the 4-way adapter.

My next long term project is to add a backup camera. The wiring figured out will be helpful. I think I will use the accessory wire to power the backup camera full-time, so I can use it in place of a rear-view mirror. Hopefully the voltage drop is not that significant to be a problem.

So glad that I can use the Chinook to haul things, but I really need to do more camping. Super busy with work and other tasks around the house, and catching COVID just before our plan to go to Zion really cut down on the trip/year number this time.