G'day Fellas,

I was towing my Caravan (Trailer) recently with a mate of mine following behind with his Colorado & Caravan.
When we pulled over for a break he said 'don't you ever your brakes?'

He asked this because we always do a trailer light test after hitching up and before moving off.
Indicator Left, Right, Brake & tail lights checked all good.
So jumped in and tested again, All good? WTF
However it had started drizzling a little not long after leaving that morning, so I'd put on my headlights.
That being the only change from the check before taking off. So I put my headlights on and did the lights check again.
Indicator Left, Right ok, Tail lights on and good. However no brake lights came on
Turn head lights off and all good. Does the same if just park lights on.

So, has anyone encountered this odd issue.
That is; All lights and indicators work fine without head or park lights on. Put head or park lights on and you lose the 'Brake lights'???

Cheers
Reg
"Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery."fficeffice" /><O></O>
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Aussie spec Brazilian built 2005 (US 2003) F-250 Superduty 4x4 7.3Ltr Powerstroke: PHP FU2 6Pos on the Fly Chip, 6 x ISSPRO Promax Guages, Donaldson (AIS) Intake with Zoodad, Hutch'd n’ Harpoon'd, Cowl Hood, Billet Grill, AIH delete, DIY CCV & catch can, Straight Through 3½” Cummins muffler, MBRP Black Tip, RiffRaff FRx,OCR,HPx, JWVB, OME Suspension, Dual Tower shocks, Tough Dog RTC Steering Damper, ARB Air Lockers Front & Rear, V10 Tranny cooler in series with Stock Tranny cooler, BD Deep Pan, Extra Cooling rear diff cover, ARB HD Front Diff cover, ARB Bull Bar, Kymar Dual Spare Wheel carrier & Rear bumper, Edge Evo Dash Pod (used for PIDs/Codes only), Long Range Fuel Tank, OEM Style paint matched wheel arch flares, VMS in Dash GPS Street & Off Road Navigator, Toyo OPAT AT 305 70R 16” on 10” Rims. GVWR (GVM) Upgrade to 5,000kg(F350).

 

Well my first thought would be because your steering wheel is on the wrong side, but that's probably not it.


A bad ground is a very small possibility. More than likely you've got a shorted wire somewhere. When you turn the headlights on, do the trailer lights come on in a dim manner, and then flash from dim to bright when you use the turn signal? The running lights should give you dim tail lights and the brake pedal should make them brighter. My guess is something has shorted and is causing the brighter brake light to be on all the time when you turn the headlights on.

If that's the case, and assuming your wire colors are the same as ours, white is ground, brown is running lights and the yellow/green are turn signals. Try cutting or disconnecting one of the turn signal wires (yellow & green) at the trailer plug. If the bright tail lights go dim when you disconnect one of those wires, there's a short in that wire that is causing the brake lights to stay on all the time.

 

Clean your plug and your connections and recheck your ground and I bet the problem goes away. I think you are losing current under increased load.

Steve

 

Would you have by chance replaced the plug on the trailer at any time in the past? If so than check the inside for corrosion. Had one do something similar and that is what it was.

 

Every time something odd with 12V happens. I look for a bad ground first. Just my .02

 

Always

Steve

 

If the ground dosent fix it, check to be sure one of your brake/turn bulbs isnt turned in the socket or has an 1156 bulb in it. Just my .02.

 

G'day Fellas,

I finally got time to get into finding out my problem.
I never tow at night so haven't let it concern me too much.

Anyway I re-did all the wireing ensureing they were properly spliced off the correct wire lume etc. Soldered them all and shrink wraped the connections. Ensured a very good earth/return earth etc.

Still no joy.

I came to the conclusion it was to do with the LED Trailer lights.
Yesterday I decided to remove the LED Tail and Stop lights and jury rig an incandecent combination tail come stop lamp.

I simply soldered a wire to the tail and stop light and sodered and earth to the bare bulb.

Poked the wires into the LED socket on one side and bingo all worked perfectly on that one side.

So I plugged the LED light back into the other side at the same time and the symptom reappeared. That is no Stop Light when head lights turned on.

So Removed the LED and soldered another bulb the same as the other side and poked tose wires into that side's LED socket so as to have both sides jury rigged to and incandecent bulb; and bingo all work a treat .

So it appears to be that the very low draw on LED trailer/caravan lights is what has caused my issue?

Now is this a common problem with these trucks?
If so is there some sort of inline connector/resistance magic box available to fix this?

Cheers,
Reg

 

My bet is the wrong LED bulb, it shouldn't be the truck.

 

G'dayM8,

I am aware that the issue is not the truck as all works well with standard bulb type trailer lights.

However several makes and models of vehicles have issues with LED lights on trailers/caravans. I've even talked to fellas who have had problems with LED lights fitted to the trucks own try backs.

This is manily with the Left & Right Indicators blinking too fast or not at all.
This is easily fixed by adding a resistor specific for Auto LED indicators.

LED lights draw such low current that some vehicle's controllers do not detect a current draw and the relays do do not operate. Put a resistor in between the indicator power and return to earth and that load gets detected and all works well.

However my issue is with the LED Stop Lights not working whenever the headlights are switched on. They work fine and bright without headlights on.

So I'm just wondering if there is some magic box on the market which could be fitted in between the truck's trailer wireing and the trailer plug .

Cheers,
Reg

 

I see, my mind was on the wrong path. I pull a lot for work, and almost everything has LED bulbs. When we have similar issues, it is usually the ground. All of our stuff is both grounded through the plug and through the hitch. We did have a run with LED bulbs that had 5 LED's, but we switched to a brand with 11 LED's IIRC. I don't know of a magic box that adds resistance, but if you have a marker light on each side of the trailer, switch them to an incandescent bulb. The resistance may be enough to solve your problem without adding too much draw.

 

Maybe this will help, post #6, https://www.ford-trucks.com/forums/1...l-problem.html I hope it shed some light! Pun intended...do I hear crickets?