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Need help with 12v trailer lights

maxxplanck

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I feel like a big dumb @#$, I hate trailer lights and anything electrical. When I bought my deuce it came with a 2" reciever hitch and a 4 wire set up for trailer lights " wiring done for brake/ turn lights no tail lights " Im going to tow another deuce next week and I wanted to use my magnetic trailer lights. The lights work checked them out on my pickup, but they dont work on the deuce. Im including pictures, the brown wire is not connected to anything not sure were it goes any help would be great. Thanks Richaua
 

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mistaken1

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I wonder where the PO found 12V for the brake and turn lights on that 4-wire flat connector.

Sorry I cannot be of any real help.

Looks like he is using relays to get 24V to control 12V. I am assuming that there is a 12V constant feed coming off one of the batteries (the one that has the negative post connected to the frame). If that is the case a quick fix would be to connect that brown wire to that 12V positive feed. You will have 12V lights all of the time though (disconnecting the 4-wire plug would shut the trailer lights off if stopped for an extended period of time).

Otherwise need to look in the manual to find which wire controls the tail lights and use it to control a third relay that will send 12V to the brown wire when the lights are on.
 
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glcaines

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You can also replace the 12V bulbs in your magnetic light set with 24V bulbs. Then, you don't need relays and the whole setup is much simpler.
 

jamboly

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The first thing I would check to see is if you are getting the voltages you need on the plug on the truck. Usually, the weakest link on these types of set ups is that the ground wire isn't making a good connections where it is connected to ground on the truck. Are you sure the 12V feed to the relays are still hooked up?
 

quickfarms

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Probably the 12volt is coming from the low side battery.

If none of the lights are working check

The power source
the ground
and each relay
Last but not least check every connection

If the only the marker and tail lights are not working
you need to find out where that brown wire is supposed to go.

The military did set some trucks up to power both 24 volt lights and 12 volt lights. They would use resisters to drop the 24 volts to 12 volts. Very simple and it works best if it is done on the trailer due to the fact that the number of lights effects the size of the resistor, remember OHM's Law
 

glcaines

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I should have mentioned also that the set of magnetic lights I purchased at Northern Tool were wired to the plug incorrectly. I took them back but all of their sets were wired incorrectly. I cut the wires and reconnected the plug correctly. No problems after that. There was a schematic that came with the set clearly showing how the plug should have been wired.
 

doghead

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All the cheap Harbor freight lights are wrong also.
 

mistaken1

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I should have mentioned also that the set of magnetic lights I purchased at Northern Tool were wired to the plug incorrectly. I took them back but all of their sets were wired incorrectly. I cut the wires and reconnected the plug correctly. No problems after that. There was a schematic that came with the set clearly showing how the plug should have been wired.
It seems they are all wrong. I just opened up the lights and swapped the wires there so I did not need to cut the molded plug off.
 

Cobra2401

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I have a pair of harbor freight magnetic tow lights also. I replaced the bulbs with 24v bulbs. The turn signals and running lights work. But when you put your foot on the brakes, the tow lights go out. When youmtske your foot off the brakes, the lights come back on. Any ideas? Thanks.
 

VPed

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Your problem is probably with a faulty ground connection, based on this symptom.
 

doghead

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I think every set if HF tow lights I have bought, were wired incorrectly.
 
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