Ford Ranger PX - LED trailer lights

Forums › Home Workshop DIY › Ford Ranger PX - LED trailer lights

chimera

506 posts

Ultimate Geek

#265668 4-Feb-2020 15:04

Posting this as an FYI, coz I searched everywhere for the best and cost-effective way to do but struggled finding the info for my Ford Ranger PX, so hopefully helps someone else out once this page gets indexed by Google ;-)

I bought a Jetski and the trailer that it came on had LED lights. I got the hyper-flashing issue (where indicators flash at double speed) It's a common problem for many vehicles with trailers that run LED bulbs. Fixes are as follows (I'll post links so you can click to see images, but basically buy these parts almost anywhere)

1. Changing your car to an electronic relay (for example an "EP27")

https://www.ebay.com/itm/12V-5Pin-EP27-LED-Flasher-Relay-Car-Turn-Signal-Indicator-Blinker-Flash-Black/163921094292

2. Wire in load resistors, one for each indicator bulb, to take "load" off the LED bulbs and make them flash normally

https://www.emax.co.nz/index.php?main_page=product_info&cPath=9855_10083&products_id=6842

3. Buy and use a "Genuine Ford PX Ranger LED Light Trailer Adaptor/Plug/Loom Resistor Focus Towbar", eg:

https://www.ebay.com/itm/Genuine-Ford-PX-Ranger-LED-Light-Trailer-Adaptor-Plug-Loom-Resistor-Focus-Towbar/151511629652

Option 1 was most appealing, but unfortunately this is only relevant on older (< 2011 I think) model Rangers (I also understand that Ford Ranger PX2+ were fixed to work with trailers with LEDs) Cost for EP27 around $40.

Option 3 was the easiest solution, but didn't really appeal because it was a part that could be lost or stolen quite easily. Also expensive, $200+ in NZ (or about $120 via eBay)

So I went with Option 2, also the cheapest ($10 plus $5 for a switch) however I also have a normal trailer with incandescent bulbs and apparently you shouldn't run load resistors with normal bulbs, so I wired the load resistors onto the wiring loom under the rear of the truck that goes to the plug. I also wired them via a toggle switch, so I can simply reach up and flick the switch down for LEDs (pulls load resistors into the circuit) or flick the switch up for incandescent bulbs (removes the load resistors from the circuit) Only a slight pain really as I'm bending down to put the trailer on the tow bar anyways. I wired them onto the truck itself rather than the trailer with LED lights, in case I need to tow another trailer that has LED lights, plus there isn't a great deal of room to mount the load resistors on the trailer itself. A suitable workaround for my requirements.

Main downside of load resistors is they can get pretty hot, so I mounted onto a metal surface to help draw heat away. I also mounted them high as I could so if reversing the jetski into the drink, they're still away from the water.

1 | 2

8955 posts

Uber Geek

#2412537 4-Feb-2020 16:25

The option 3 is just a trailer plug-socket with a couple of resistors across some circuits - will see if I can dig up the info. For a few cents, you can just wire the resistors into the plug on the trailer, if you use the same trailer all the time.

chimera

506 posts

Ultimate Geek

#2412562 4-Feb-2020 16:53

Yeah indeed, option 3 is effectively the same as option 2, it's just in a pretty little adapter cable that's extraordinarily overpriced :-)

I wired load resistors at the vehicle and not the trailer, quite simply in case I have to tow another trailer with LED lights. I figured I'd sort the issue at the source rather than the symptom.

I also read wiring normal resistors into the trailer plug (eg: without heat sinks) is not recommended due to the very reason they come with a heat sinks - they get hot. If you wire in normal resistors, they will fit but likely blow if they get too hot - I guess it depends on how long you're waiting at the lights with your indicator on ;-)

If you can fit load resistors into the trailer plug itself then you clearly have one large plug, unless of course you're do something like this lol...

RunningMan

8955 posts

Uber Geek

#2412577 4-Feb-2020 17:55

No, that's not the case. With option 3 they are not a load resistor that simulates the load of an incandescent globe (like what you have pictured). The original Ford adapter quite happily fits them inside the plug.

RunningMan

8955 posts

Uber Geek

#2412590 4-Feb-2020 18:03

120 ohm 2 watt resistors x 4. 1 each from stop/tail/left/right to ground. Should easily fit inside the trailer plug. They are not there for a big load like the usual LED flashing problem, the signal the trailer controller that a trailer is connected. It should also turn the reversing sensors off.

MartinGZ

359 posts

Ultimate Geek

Subscriber

#2416099 11-Feb-2020 12:08

Shouldn't this post be in Transport cars?

It's a shame I hadn't seen @RunningMan's post a year ago as he is quite right. Here's a picture of the genuine Ford adaptor:

I had a play around with it and certainly the resistors ran hot, but one would suppose Ford did there sums.

As I didn't want to use the Ford adaptor (the caravan lead is too stiff to have an additional length) I built a box into the caravan. If doing it now, I would use the smaller resistors. I didn't include a resistor for the tail lights as they seemed to work OK.

I have a PX2 Ranger where this issue is supposed to be sorted, but it certainly wasn't on my one.

Nokia 6110, 6210, 6234, Sony Ericsson XPERIA X1, Huawei Ideos X5 (Windows Mobile), Samsung Galaxy SIII, LG G4, OnePlus 5, iPhone Xs Max (briefly), S21 Ultra. And I thought I hadn't had many phones - but the first one around 1997.

RunningMan

8955 posts

Uber Geek

#2416106 11-Feb-2020 12:19

Remember they are not load resistors as such. It's not just about getting the lights to flash properly, they are there to signal to the trailer controller that there is a trailer connected. That then changes some things about how the vehicle operates like reverse sensors and stability control (trailer anti sway activated etc.). Don't wire them directly into the vehicle as suggested above as you may find your stability control doesn't work if you need it...

chimera

506 posts

Ultimate Geek

#2416167 11-Feb-2020 13:35

I have no stability warning lights on my dash nor does an ODB scan indicate any issues with the trailer connected and resistors in place. In fact, in my PX Ranger, there is no "trailer detected" light on my dash to visually tell me that a trailer is connected either (that I've seen in some other vehicles) so unless this is a feature in PX2 or higher I don't know.

I also cannot see how running a resistor for each indicator light on the vehicle is any different than using the Ford trailer adapter. From what I have read, vehicles senses a trailer is connected via the running lights and brake lights, not indicator lights. There is no resistor put in the brake circuit (and obviously no need for one) as this is purely to fix the hyper-flashing issue I have, so there should be no change to the signal that the vehicle sees with a trailer connected.

Additionally, wiring this in to suit the trailer bulb types is obviously required - but in my case it's the reason why I wired in a switch on my vehicle to "engage" or "disengage" the resistors for LED vs incandescent bulbs on the trailer - resistors in the circuit for LED, out of circuit for incandescent.

Happy to be proved wrong, if anyone can explain why otherwise.

GoodSync

GoodSync. Easily back up and sync your files with GoodSync. Simple and secure file backup and synchronisation software will ensure that your files are never lost (affiliate link).

RunningMan

8955 posts

Uber Geek

#2416169 11-Feb-2020 13:44

chimera:[snip]I also cannot see how running a resistor for each indicator light on the vehicle is any different than using the Ford trailer adapter.

The resistor on the vehicle is always there, the trailer adapter is presumably only connected when the trailer is. If there are resistors on the vehicle all the time, it thinks there is a trailer there all the time and modifies the vehicle behaviour accordingly.

Have a read of the BEM

chimera

506 posts

Ultimate Geek

#2416173 11-Feb-2020 13:56

RunningMan:

chimera:[snip]I also cannot see how running a resistor for each indicator light on the vehicle is any different than using the Ford trailer adapter.

The resistor on the vehicle is always there, the trailer adapter is presumably only connected when the trailer is. If there are resistors on the vehicle all the time, it thinks there is a trailer there all the time and modifies the vehicle behaviour accordingly.

Have a read of the BEM

Hence the on/off switch... however detection is relevant to the brake system, so again should be irrelevant.

This is for the F150, but I assume Ford keep this as standard across their models...

https://www.f150forum.com/f118/trailer-detection-just-facts-408246/

MartinGZ

359 posts

Ultimate Geek

Subscriber

#3123009 2-Sep-2023 16:00

I had a PM asking how I fitted the load resistors.

Every caravan is different, but you need to find where you can connect into the wiring loom in order to pick up the relevant wires. I got lucky and found them all in the rear fairing that held the RH tail-lights. Shown in the following photo.

On the top left you can see a small patch lead. This was removed and the connectors taken off (so I could put heatshrink on.) Wires were soldered onto this as shown below.

Another connector was put on my flying patch leads with the mating connector fitted to my resistor box which is shown in a post above. This was refitted as shown below.

The final assembly is in the following photo. The box is bolted to the fairing and can be removed if need. All you can see from the outside is two small bolts painted black.

I hope this helps.

MartinGZ

359 posts

Ultimate Geek

Subscriber

#3123010 2-Sep-2023 16:06

This is an issue with ALL Rangers, I've had the last three models including the latest one. The following is a quote from the MY2022 Ranger body manual:

"The Trailer Tow Module (TTM) can support pure
LED trailer lamps as long as each circuit exceeds
500mA, below this and the system will not detect
a trailer has been connected and shuts down all
outputs (sleep mode). It is recommended to
target a 550mA minimum load to allow for
system tolerances.
If the LED lamps on the trailer fall outside specific
tolerances, customers can experience the
following symptoms on the vehicle when LED
trailer lamps are connected to the vehicle:

• LED trailer lamps flickering when lamps are not
in use
• DAT (Driver Aid Technology) not being
disabled
• Rear park sensors (where fitted) continually
fire in Reverse gear when a trailer is connected
to the vehicle
• Vehicle does NOT acknowledge that a trailer
has been connected when it has (either
through Icon on centre screen OR message on
the instrument cluster Multi-Function display)
• "Check trailer park lamps" OR "Check trailer
brake lamps" warnings appear on the
instrument cluster Multi-Function display

In order to correct this, supplemental load
resistors would need to be used to meet the target
system tolerances."

barrg0

8 posts

Wannabe Geek

#3123133 2-Sep-2023 21:37

Thank you for this very informative post on how you went about getting around this annoying problem with the Ford Ranger and led trailer lights. I'm sure many more Ranger owners will appreciate the work you have put in to post this. Well done.

barrg0

shim99

104 posts

Master Geek

ID Verified

#3123220 3-Sep-2023 11:05

I had a similar problem in our landrover and came up with a switched solution that sits in the cubby near the rear lights. This approach means I can use it for different towing situations depending on the light set up of the trailer. The box has two resistors in it and an on/off switch. Doesn’t heat up much at all. If I ever sell I can just unplug the box and use in the next vehicle if needed.

barrg0

8 posts

Wannabe Geek

#3129203 18-Sep-2023 23:53

Hi Martin,

Ive just installed a similar resistor box in my Jayco van using the same resistors that are used here. It has now fixed the indicator lights but the tail lights are still flashing. Is there another type of resistor I could try for the tail lights? The brake lights are working ok without a resistor. Any help would be greatly appreciated.

Cheers

MartinGZ

359 posts

Ultimate Geek

Subscriber

#3129356 19-Sep-2023 10:28

I'm no electrical expert, but 120 Ohm seems plenty. As above, Ford state 500 mA current which implies a resistor of 24 Ohm at 12 VDC. I'd check:

Connection - is it actually the tail light wire you've hooked into.
Whether the resistor is actually as stated.
All your terminals are tight.
Does it work if you take that resistor out.

I actually left the resistor off the tail light circuit as I found it didn't need it. That circuit is tail lights, running lights, and rear camera on the caravan, so probably enough anyway.

1 | 2