Stumped trying to wire trailer

[justinae]

Hi all. First time Mazda/Ford Ranger owner and first post here on the thread. I'm a general contractor in Portland and retired my 1980 Datsun 720 as a work vehicle and upgraded to the B4000. So far really happy with it, except gas mileage stinks.

Anyway, I've spent way too much time trying to figure out how to wire up my trailer. Specifically the towing vehicle side. I tapped the wires as follows:

Yellow harness wire --> Light green/orange stripe on the left
Green harness wire --> Orange w/ light blue strip on the right
Brown harness wire --> I tapped into each of the brown wires going to the brake light on both sides and joined them into one wire which goes to the harness
White --> Grounded to frame

With this setup, everything works fine on the truck, but nothing on the trailer. Originally I set it up with tapping the brown into the black wire that also went into the turn signal on each side. So again, a brown coming from each side, joined, then harnessed. When it was setup like this the turn signals worked fine but no brakes on the trailer.

Attached are a couple pics. The previous owner had a front mount towing harness setup.

Seems the problem is with the brown but I've tried a lot of combinations. I tried connecting to all three colors coming into the brake light and that just shorted the fuse.

You can see from the first pic that there is a lot going on. There is a canopy that has a brake light, which also taps into the brown coming from the truck brake.

Any help appreciated.
Justin

 

[Earl43P]

My 93 schematic says Stop Lamp is LG (light green).

Parking lamp is Brown wire.

 

[justinae]

Really? I wonder why the brown wire from the front wiring harness is tapped into the brown. I did try all three colors from the brake but I'll try the light green again.

Thanks!

 

[alwaysFlOoReD]

On the trailer, IIRC;
white=ground
green=left turn/brake
yellow=right turn/brake [green and yellow may be opposite, I'm not sure]
brown=park/running lights
On the truck use a test light to find the corresponding wires and tap into them. Some vehicles need diodes to prevent cross currents between turn signals and brakes, you can buy them pre-made for any vehicle [they are generic], I don't know if yours will need that.
I'd also invest in di-electric grease [or whatever the grease is called when using on electrical circuits] or use silicone to seal the taps that you use to prevent corrosion.
Good luck,

Richard

 

[bobbywalter]

strongly suggest to use posilocks or solder those connections

 

[leviticus2629]

On a 4 wire trailer plug, green is right turn, yellow is left turn, brown is marker lights, and white is ground.
If you have separate brake lights and turn signals on your truck ( red brake lights, amber turn signals) you need a tail light converter. A test light is the best way to find the wires you are looking for on your truck, as previously stated. Tail light converters are easily found at an auto parts store, and usually have a sticker on them saying what goes where, very,very easy to figure out.

 

[alwaysFlOoReD]

^^^ Thanks for the clarifications, I don't do that wiring stuff often enough to mremember all the little details

Richard

 

[justinae]

Leviticus thank you. I would have pulled all my hair out trying to figure that out. So is that what the black thing is in the first picture which is going to the front harness from when the truck was pulled behind a motor home?

 

[justinae]

Before I go buy a new converter. Can I tap into the existing one? I'm assuming I would tap into the wires after the converter. Is there an issue with having both a front and a rear trailer harness?

 

[leviticus2629]

Before I go buy a new converter. Can I tap into the existing one? I'm assuming I would tap into the wires after the converter. Is there an issue with having both a front and a rear trailer harness?

The black thing in the first picture doesn't look like a tail light converter to me, at least not any that I have seen and I work with trailer wiring every day.
For what it costs for a basic tail light converter (usually $20) I would personally buy a new one, and tap into the wires coming right off the tail light assembly, using a test light to be sure. I am usually very cheap, but I guarantee you will have less headaches starting with wiring all done by yourself, FWIW.

 

[justinae]

Ok, that sounds like a good plan. Thank you very much. I'll grab a converter, maybe even tonight. I need to get this solved.

Out of curiosity, if there is already a front two harness, shouldn't I be able to tap into those wires? Seems like if it's supplying one harness it could supply the other. I did try that by the way and it didn't work.

 

[leviticus2629]

Ok, that sounds like a good plan. Thank you very much. I'll grab a converter, maybe even tonight. I need to get this solved.

Out of curiosity, if there is already a front two harness, shouldn't I be able to tap into those wires? Seems like if it's supplying one harness it could supply the other. I did try that by the way and it didn't work.

Although I do not generally deal with cars being towed by motorhomes, my understanding is that the converter needed is opposite of what you need, because the motorhome will generally have brake lights and turn signals on the same bulb.
I am not overly familiar with that box from your picture, and with out being there to figure out for myself it is hard to say what you could do with it.

Using a test light is key and will take A LOT of the guess work out of the process. Also, if you are using those blue stripless connectors, I hope they will not not see any road salt, or don't expect them to last more than a couple years.
If you do use them, do not leave the exposed end of the wire sticking out of them like they are in some of the connections in the pictures.