Power to trailer

[Jimmyt321]

Hello. I'm new. Getting ready to travel with a small pop up.

My truck is a 1996 Ranger 6cyl 4.0 xlt.
I am getting no lights to trailer. Bought small tester and nothing coming from the truck.
Underneath there is this little convertor from Uhaul. Not sure if that a problem. Its sealed. Can it be bad? A picture of it is included. Along with the little tester. Also, the 4 way on the truck, which has to female connections.
Where do I start troubleshooting from here?
Thanks,
Jim

 

[dirtymike]

I took something similar out (little convertor from Uhaul) of a jeep 4X4 that was towed behind a RV. Not sure what it was though. Im sure someone here has the answer. They will chime in soon. Hold tight.

 

[dirtymike]

In the tech section of this forum there is a trailer wiring diagram. Have you search this section.

 

[dvdswan]

Welcome to the site.

 

[RonD]

Welcome to TRS

It is what is says it is on the label

3 wire to 2 wire converter

Some trailers just have 1 dual filament Bulb on each side at the rear
Park light is one filament
brake/turn is the 2nd filament
Most trailers do use the 2 wire system, so 4 wire connector, ground, park, left and right
Trailer wiring diagrams seen here: https://www.therangerstation.com/tech_library/TrailerLights.shtml

1993-1999 Rangers use 3 wire system, they have separate turn signal bulbs on each side
So instead of rewiring the trailer with 2 more lights/bulbs for turn signals, its just easier to use one of these converters

There is also a 2 wire to 3 wire converter to go the other way, if trailer has separate turn signal bulbs

So first you need to know what the trailer uses, does it have 3 wires at each tail light(NOT counting a ground wire)
Or just 2
3 is park, brake, turn
2 is park, brake/turn

Could the module be bad, sure, they are pretty weather proof though
Usually its the Splice connections used to add this module that fail, this is assuming the trucks park, brake and turn bulbs all work

1996 won't have separate fused trailer light wires, so if rear lights are working then the power is AT the drivers side rear of the truck
Ground is a big deal for trailer lights, since the trailer not part of the truck it has no connection to battery negative(ground) in the truck, so the ground wire for the trailer is as important as the 12volt wires

When you are testing for voltage there is no 12volts unless there is 0 volts(battery negative/ground)

None of the wires will show any voltage if that one ground wire is bad, just FYI

 

[Jimmyt321]

Welcome to TRS

It is what is says it is on the label

3 wire to 2 wire converter

Some trailers just have 1 dual filament Bulb on each side at the rear
Park light is one filament
brake/turn is the 2nd filament
Most trailers do use the 2 wire system, so 4 wire connector, ground, park, left and right
Trailer wiring diagrams seen here: https://www.therangerstation.com/tech_library/TrailerLights.shtml

1993-1999 Rangers use 3 wire system, they have separate turn signal bulbs on each side
So instead of rewiring the trailer with 2 more lights/bulbs for turn signals, its just easier to use one of these converters

There is also a 2 wire to 3 wire converter to go the other way, if trailer has separate turn signal bulbs

So first you need to know what the trailer uses, does it have 3 wires at each tail light(NOT counting a ground wire)
Or just 2
3 is park, brake, turn
2 is park, brake/turn

Could the module be bad, sure, they are pretty weather proof though
Usually its the Splice connections used to add this module that fail, this is assuming the trucks park, brake and turn bulbs all work

1996 won't have separate fused trailer light wires, so if rear lights are working then the power is AT the drivers side rear of the truck
Ground is a big deal for trailer lights, since the trailer not part of the truck it has no connection to battery negative(ground) in the truck, so the ground wire for the trailer is as important as the 12volt wires

When you are testing for voltage there is no 12volts unless there is 0 volts(battery negative/ground)

None of the wires will show any voltage if that one ground wire is bad, just FYI

Thanks. Electric is one thing I no nothing about. I assumed these plugs are plug and go.
I have read many discussions that mention the importance of the ground wire.
Isn't the ground wire inside/part of the 4 way plug?
How do I go about troubleshooting or finding out about the ground wire?
I'm not sure what to do next. Cut and put in new wires?

 

[RonD]

You will want to invest in a 12volt Test light that has a sharp tip, so it can pierce wire insulation, and an alligator clip to clamp to a good ground
This is a must have for trailer light wiring

A Volt/OHM meter is good as well but only if you want to learn to use it

You test a ground by turning on Park lights then test for power on the BROWN wire at the back of truck using bare metal as a ground
When you have the 12v showing then move the ground over to the trailer ground, should still have 12v, if not then trailer ground is bad

 

[Jimmyt321]

Thanks.
Also, the wires coming from the converter to the plug are in bad shape. Cracked/peeling...open spots.
I have this with me.
Maybe first cut and splice from the converter box where the wires are still in good shape?

 

[RonD]

I would try to get whats there working by cleaning up the wires, cut and resplice as needed and always check if the truck lights are still working after each change

Once you have old setup working or find out you need another 3 wire to 2 wire unit, then replace that

I wouldn't add any new parts, even that end connector until you are done, up to you, but my time on this earth has taught me a few things, one of which is don't add possible complications until you have fixed the first problem, lol


And its a "new" part, so 15-20% chance one of the 4 wires in bad inside the connector, lol

 

[Jimmyt321]

Thanks Ron!

 

[don4331]

The tool you need looks like this: https://www.canadiantire.ca/en/pdp/oemtools-6-12-volt-circuit-tester-0250934p.html#plp

Start on the "truck" side" and see if you have power for each of wires. Starting with Tail with park lines on for the truck, If you have power in the 'Tail' wire, move to ground, then moving to signal lights and finally brakes (which usually requires an assist). If you have power and ground, then move to the trailer side

Repeat on trailer side.

The one thing I would check (because all my trucks have it),is right in center of truck, where the connector is for the frame to wiring is, if there an OEM pigtail for trailer wiring. In which case, you go to Ford (or salvage yard) and get the OEM trailer wiring (the difference for ALL my Rangers as to whether they had trailer wiring or not was simply the 12" pigtail...)

I know that slightly goes against Ron's philosophy of adding parts, but for me going with OEM solution and bypassing the aftermarket solution wins every time.

On the other hand, for my S-10 (yes, I was young and foolish once) I used a similar adapter to what you are showing. Again it installed between the frame and bed wiring. https://www.etrailer.com/Custom-Fit...Ranger/1996/118325.html?VehicleID=19961172318. Beats the heck out of cutting/splicing wires.

 

[RonD]

If/when you get a 12v test light, test on your battery first, in BOTH directions, i.e. pointy end on positive and clip on negative, then reverse them, pointy end on negative, clip on positive, should light up either way

Most new ones will be LED bulbs and have a built in polarity circuit, so there should be no difference in what end is on what polarity, should light up regardless

LED bulbs have a polarity, LED = Light Emitting DIODE, and diodes only pass power in one direction, unless you add a polarity circuit, then they have no polarity, just need a + and -

 

[lil_Blue_Ford]

Yeah, vehicle electric can be a little tricky until you get the hang of it. I have a hatred towards the 4 pin flat plugs, for me they seem to corrode to junk inside the plug in short order. So that’s something to check too, see if the 4 pin flat on the truck is corroded inside. If you do have to splice any wires, use solder and heat shrink or solder shrink. Otherwise you are just asking for corrosion in the vehicle wiring.

 

[Jimmyt321]

Thanks guys Tested it. Power (blinkers, etc) to the wires before going into the converter, dead coming out.
I know the converter brings it down to 4 wires coming out.
Can I use this? It's the same set up. 5 in, 4 out.
Thanks

 

[Snoranger]

Thanks guys Tested it. Power (blinkers, etc) to the wires before going into the converter, dead coming out.
I know the converter brings it down to 4 wires coming out.
Can I use this? It's the same set up. 5 in, 4 out.
Thanks

No.