I have a 2012 F250 (Diesel) with factory wiring for my trailer. I have multiple trailers - all are setup for 7 pin round plug. The new trailer works fine -- all lights are operational. The other two trailers -- only the running lights and electric brakes work. The stop/turn lights do not work. I have traced the wiring and checked the bulbs. The one thing I noticed with one trailer today is that the leads inside the round plug get extremely hot......any ideas are appreciated!!
You have to many bulbs running for the size wire you can get into a 7 pin plug. You will have to up grade to a heavy vehicle plug which is around 2" in dia.. Next the stop light draw 25 watts each so if you have 3 trailers that ia 6 x25 watts x12 volts will indicate how many amps you are pulling when the brakes come on. Next you can change the wiring so that each bulb is connected in parallel not series that is the first 2 lights have one wire the 2nd bulbs will have a different wire out of the same pin and so on for the rest of the trailers. So what you will have will be say for 3 trailers the trailer plug will have wire to the first trailer and out of the same pin will be another wire that will go to the socket for the second trailer and so on That way the wire carrying the load will be the vehicle wire that you should have relayed any way. So you have a big current wire to the relay that is connected to the power pin of the socket. The relay is activated by the stop light wire to earth. This closes the relay and the heavy wire conducts current directly to the stop light pin of the first trailer and is piggy backed to the second socket and so on.. IN the end you will have only 2 bulbs working on each wire and not a multiple of bulbs drawing current on the one wire
SOURCE: 2004 F250 No brakelights/turn lights on trailer
You will need to get a 12 volt test light and check the trailer connector for a voltage signal to the trailer, it may also have seperate fuses under the hood for the trailer lights if the system is factory installed, federal law requires the 2 systems be isolated, if there are blown fuses find the short in the trailer before replacing fuse(s), with no exceptions the short is always in the trailer. Hint, check the fuses 1st.
SOURCE: 1998 4runner trailer light wiring not working
I recommend that you tighten the ground wire screw for starters. since the vehicle is ten years old corrosion may be the culprit.
SOURCE: car to trailer wiring problem
most likely the trailer wires dont match the truck wires. you will need to verify that the truck is wired correctly and then that the trailer is wired to match your truck. problems usually arise after someone has BORROWED a tralier and made the trailer wires match THEIR truck trailer wiring here is standardized but people wire them up any way the can, and it causes problems when that trailer is borrowed or sold.
SOURCE: Trailer brakes
Take a 12 volt test light... the kind that has a spring loaded clip to hold the probe into the wire, and insert it into the wire just before the trailer plug, vehicle side. (Blue I think) If there is a connection, the brake should see it and you should have an indicator light. When you activate the brake the test light should lite up. If not, move up to the brake actuator and test the blue wire. If there is nothing at the actuator, check the black wire. It is power to the controller. If no power there, check fuses again. If it does pick it up at the plug, connect the trailer and test the trailer itself. First ground to the trailer and then to the truck. Most problems are ground wire related. Then move to the axle and test it there. For the brakes to work, and even show on the indicator, there has to be a ground and power to the brakes themselves. There are 2 wires to each brake... a ground and a power. Test across both wires to make sure you have power and ground. You can also hook another trailer to your truck or another truck to your trailer. Lights can work through trailer ball ground. Brakes can't. leave the trailer unhooked from the trailer and hook the wiring up and test the lights. That usually will indicate a good or faulty ground. Also make sure there is a GOOD ground to the truck frame/body. Also try http://www.etrailer.com/faq-wiring.aspx. They have a great website with lots of info. Hope this helps. Mike
SOURCE: 03 Ford F250 does not send power to trailer plug
Go to your fuse box in the engine compartment. Check the fuses in the box. Your turn signals and brakes to your trialer are controlled fron fuses in that box not inside the truck!
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Sorry -- seems like you have the impression I am trying to hook up all three at once....I am not. When I use one trailer all lights work fine -- the other two trailers when used separately -- stop/turn lights do not work
OK now I get the picture. Check the wiring is done correctly for each trailer plug and check for the earth wire in each plug. You may have the stop/ clearence wires in the wrong pin
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