Trailer Lights Wiring Issue w/ Ranger

[reginald fairfield]

Hello everyone,

I am having an issue with my Ranger, maybe ya'll have had the same problem. I have the 4 prong flat trailer wire harness that is standard on all rangers. The thing sends out a current for brake lights, turn signals, and hazards, but it will not send out a current for marker lights. I have tried jimmying it around to get it to work but no dice. Is there a fuse somewhere that can go out or something? Any experience with marker lights not working on trailer when hooked on your ranger?

Danke,

RF

 

[alwaysFlOoReD]

Are the lights on your truck working? I would use a test light at the truck end to see if you have power at the plug. Then note the color of the wire you are tracing and follow it back until it doesn't work, and look for the problem there. Or if it's working, trace back on the trailer side untill you find the problem.
Most times the problem is a bad ground though.

Richard

 

[fyre82]

I have the same 4 wire flat. Your running lights should work fine when wired to the correct post.

The four wires should do the following:
rt turn
lt turn
brake - splits into 2 wires
running/park/license lights

Use a test light to see which post has power when you turn on the truck lights. Wire the running lights to that post.
If you don't have a wire that's hot in the lights on position then the wiring to the plug isn't correct. Go under the truck and find which wire it is in the loom and rewire accordingly.
There is also a trailer wire 'tap' T that plugs into the loom that could make it easier.

I would also suggest grounding your trailer loom to the trailer frame. This will help stop weird light behavior due to the grounds not being sufficient.

This is what I have:

I would go out and look at my setup but I'm not mobile at the moment.



Rich

 

[Explorin94]

Hello everyone,

I am having an issue with my Ranger, maybe ya'll have had the same problem. I have the 4 prong flat trailer wire harness that is standard on all rangers. The thing sends out a current for brake lights, turn signals, and hazards, but it will not send out a current for marker lights. I have tried jimmying it around to get it to work but no dice. Is there a fuse somewhere that can go out or something? Any experience with marker lights not working on trailer when hooked on your ranger?

Danke,

RF

Is this a factory harness pigtail or aftermarket?
The flat 4 should have....
yellow wire- left turn and brake
green wire- right turn and brake
brown wire- marker, tail and license plate
white wire- ground

Some trucks have fuses in the fuse box under the hood. I think a 10 amp. If that is blown then you may have a problem with your trailer.

 

[Grey_04]

i pull trailers constantly for my construction hobby. my set up uses the "t " connector that plugs into the factory harness. the first thing I'd do is take a test light and check for power in the flat 4 plug for each light if you have it in the plug your trailer is the problem.
I'd then start by taking the plug on the trailer and finding the white wire and cleaning the ground wire, re-crimping a wire end on that wire. take some emery paper clean the frame and reattaching the ground wire to the frame. most of my trailer lighting issues in the past has been ground problems on the trailer frame.
here's a link to the wiring diagram in trs tech library
http://www.therangerstation.com/tech_library/TrailerLights.html
just for reference here's my setup i pull..

 

[RangerSVT]

First, check your fuses. If you have factory tow package, you will have separate fuses for trailer lights and vehicle lights. Second, NEVER use a test light on newer vehicles, you can damage circuits by using a test light as this pulls too much amperage. And while others will argue the use of a testlight on some circuits, use a multimeter instead, it is much safer and can also tell you how much voltage you have in a circuit, not whether it is "on or off"...
SVT

 

[alwaysFlOoReD]

First, check your fuses. If you have factory tow package, you will have separate fuses for trailer lights and vehicle lights. Second, NEVER use a test light on newer vehicles, you can damage circuits by using a test light as this pulls too much amperage. And while others will argue the use of a testlight on some circuits, use a multimeter instead, it is much safer and can also tell you how much voltage you have in a circuit, not whether it is "on or off"...
SVT

Good to know. What year does that start?

Richard

 

[Grey_04]

Good to know. What year does that start?

Richard

x2 i ran across someone having similar issues and a ford tech had a test light out in the parking lot at the dealer.. who would have thought?????

 

[RangerSVT]

Good to know. What year does that start?

Richard

IIRC 98 was the beginning year...

x2 i ran across someone having similar issues and a ford tech had a test light out in the parking lot at the dealer.. who would have thought?????

They have instruments (one is called "The Probe") that looks like test lights, but are safe to use on delicate circuits...It has two LED's on it, green for ground and red for positive, and it plugs into the cigarette lighter/Acc plug...There are others that are battery powered and do not need to be plugged up, they just require the operator to touch a ground with one hand and test the circuit with the other holding the tester...
SVT

 

[reginald fairfield]

Thanks guys,

the problem has to be in the truck, cause I hooked up another vehicle to the trailer and the running lights worked. I also already tested for a current at the truck, and no go... thats why I was thinking maybe a fuse?

The grounds are actually really good on the trailer, I do have one connected to the frame, and the ball also grounds obviously...

If anyone knows exactly where that 10 amp fuse is I would appreciate it... I will start looking myself

Thanks again fer all the input

Oh yeah, and the towing harness on the pickup is the factory one... I already took the spare off once and tried to mess with it, but I am no electrician and gave up. Too many wires.

RF

 

[RangerSVT]

I doubt it is the distribution under the hood, so check the one on side the dash, get your owner's manual out and look it up in there, it'll tell you where its located
SVT

 

[reginald fairfield]

Hey ya'll,

Problem solved!

I do not have the original owner's manual, just a haynes, and it freaking sucks, it doesn't even have a fuse box diagram. So I found a site that had one, and checked the fuses, and fuse 35 was in the 36 postion, which is not supposed to have anything. Moved the fuse, and bamo, lights work. It is a 15 amp fuse. Now that's what I call a cheap fix lol.

Thanks fellas,

RF

 

[RangerSVT]

Most often then not its fuse related....Glad you got it fixed
SVT