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Trailer inside lights don't work

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Old Apr 16, 2020 | 10:15 PM
  #1  
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Trailer inside lights don't work

Do I need to get something different to make the interior lights on a cargo trailer to work? Hooked up truck, running lights on,truck running no inside lights function. Running a 7 pin plug to factory Ford setup. Can't figure it out. Ground is good and power wire goes to the 1 o'clock position on the truck plug recepticle.
Its a 19 f350 powerstroke
 
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Old Apr 16, 2020 | 10:52 PM
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Somewhere here on FTE I read that you have to put your foot on the brake before that circuit will energize.
 
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Old Apr 17, 2020 | 06:49 AM
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Frankly, I’m not sure about what it takes to get the @#&$% “smart” trailer circuit controller to work. Assuming your truck’s trim is higher than XL, here are some things to try:

1. Does your trailer have a house battery? It might need one.
2. Are the trailer lamps LEDs? You might need an adapter to increase circuit loads.
3. Check fuses #42 (40A) and #65 (30A) in the engine compartment fuse box.
4. You might need to create and activate a trailer profile in the instrument panel trailer folder.
5. Once the trailer is hooked up and plugged in, you might need to start the engine, press the brake pedal, and put the transmission in gear to activate the trailer battery charging circuit.
6. When your truck recognizes the trailer, it should change the turn signal lane-change feature from three blinks to five.
7. With the trailer profile active, your truck’s instrument panel display should default to the trailer display when you start the engine.
8. Have you checked the trailer’s interior lights with an independent power source?

Some combination of the above may help you sort this out.

HTH,
Jim / crewzer
 
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Old Apr 17, 2020 | 07:16 AM
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Dumb question. Have your tried it on another vehicle to see if the lights work there?
 
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Old Apr 17, 2020 | 07:37 AM
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On my simple cargo trailer with no brakes, it just uses a flat 4 pin connector and the trailer interior light runs on the tailing truck circuit. How is your trailer wired?
 
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Old Apr 17, 2020 | 08:07 AM
  #6  
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Originally Posted by SDcrewzer
Frankly, I’m not sure about what it takes to get the @#&$% “smart” trailer circuit controller to work. Assuming your truck’s trim is higher than XL, here are some things to try:

1. Does your trailer have a house battery? It might need one.
2. Are the trailer lamps LEDs? You might need an adapter to increase circuit loads.
3. Check fuses #42 (40A) and #65 (30A) in the engine compartment fuse box.
4. You might need to create and activate a trailer profile in the instrument panel trailer folder.
5. Once the trailer is hooked up and plugged in, you might need to start the engine, press the brake pedal, and put the transmission in gear to activate the trailer battery charging circuit.
6. When your truck recognizes the trailer, it should change the turn signal lane-change feature from three blinks to five.
7. With the trailer profile active, your truck’s instrument panel display should default to the trailer display when you start the engine.
8. Have you checked the trailer’s interior lights with an independent power source?

Some combination of the above may help you sort this out.

HTH,
Jim / crewzer

Lariat package

1. No house battery
2. Inside is led outside is not. I switched the truck to led and forscan adjusted for led
3. I will check those fuses.
4. Profile active in truck.
5. Trailer hooked up while running but did not tap brakes. Will try that. The profile did activate however.
6. Yes it does I actually used forscan to bump regular to 5 blinks which makes trailer 7 blinks
7. Yes it does
8. Yes ran wires directly to a spare battery before wiring them in to trailer system.

I will try the depress brake pedal after hooking it up as that seems to be the general consensus. If it does work that has to be the dumbest thing ever to activate power source through 7 pin plug ever
 
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Old Apr 17, 2020 | 08:07 AM
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Originally Posted by Poncho450
Dumb question. Have your tried it on another vehicle to see if the lights work there?
No access to another truck unfortunately
 
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Old Apr 17, 2020 | 08:09 AM
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Originally Posted by Rich53
On my simple cargo trailer with no brakes, it just uses a flat 4 pin connector and the trailer interior light runs on the tailing truck circuit. How is your trailer wired?
7 pin plug. The interior lights actually go through the 7 pin. They don't go anywhere else. Traced all back to the 12 v power on the plug.
 
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Old Apr 17, 2020 | 08:24 AM
  #9  
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Well no trailer battery = no power to the trailer. Without a battery present on the trailer side the charge circuit with not turn on.
 
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Old Apr 17, 2020 | 08:43 AM
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Angry

Originally Posted by 78pace

1. No house battery

5. Trailer hooked up while running but did not tap brakes. Will try that. The profile did activate however.

I will try the depress brake pedal after hooking it up as that seems to be the general consensus. If it does work that has to be the dumbest thing ever to activate power source through 7 pin plug ever
OK. The trailer battery charging circuit may not activate without a house battery.

I’ve seen comments about depressing the brake pedal for several seconds, putting the truck in gear (and then back into neutral for testing), and even having to increase the Diesel’s idle speed.

It is indeed a stupid design, IMHO. And, again IMHO, the idiocy is compounded by the incredibly poor “instructions” In the OM.

Best of luck!
Jim / crewzer
 
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Old Apr 17, 2020 | 08:44 AM
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Lightbulb

Originally Posted by ford390gashog
Well no trailer battery = no power to the trailer. Without a battery present on the trailer side the charge circuit with not turn on.
I seem to recall this situation causing a “No trailer battery detected” message on the instrument panel.

HTH,
Jim / crewzer
 
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Old Apr 17, 2020 | 10:27 AM
  #12  
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My cargo trailer did the same thing. Had to put in gear and obviously hit brakes to have it energize. Pain in the *** imo.
 
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Old Apr 17, 2020 | 10:43 AM
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Edited due to me not reading correctly, I thought when he said 7 pin twice he meant the 7th pin on the plug which is reverse. Please disregard my comment.
 
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Old Apr 17, 2020 | 10:43 AM
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Originally Posted by ford390gashog
Well no trailer battery = no power to the trailer. Without a battery present on the trailer side the charge circuit with not turn on.
The wires are wired to the 7 pin plug on the trailer. Nothing going to anywhere else on the trailer. Using all existing wiring.
 
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Old Apr 17, 2020 | 10:45 AM
  #15  
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Originally Posted by Keith Schumaker
By 7th pin you are not using the center pin on the 7 pin harness are you? On my truck that is clearly labeled as reverse lights, 12v power is the pin one spot clockwise from the nub on the truck side.
No using the one at 1oclock on the truck side. Trailer is all factory wiring.
 
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