Trailer wiring issue.

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NateTheGreat

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2017 ram 1500 5.7l "Regular darn truck"

Mechanic all my life. USMC LAV repairman.


Trailer lights work perfect on Chevy truck. When hooked up to my dodge.... they dont work so good.

No blown fuses.
All grounds have been cleaned.
4 blade - boat trailer.

The socket is hot and working properly according to test light.

When plugged in, Right side of trailer works fine, left side does not.
The wrong filament is burning on left side for blinker/brake (1157).

Brand new trailer wire kit. Pro install. Trailer wiring is perfect. Grounds are good.

Running lights not working either.

Truck has 8000 miles, no mods, never had a trailer on it.

Ever happen to anybody?
 

1500ram12

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Did you test that each pin on the truck's trailer connector did what it is supposed to do? Is the ground for the trailer lights grounded to the trailer or ran all the way to the plug? I had a similar issue this summer on one of my trailers. Ended up having to run the ground for the lights to the plug


2018 2500 6.4L Tradesman
 
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NateTheGreat

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The pins do function properly. Its grounded to the trailer, light housings also grounded to trailer.
 

1500ram12

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If you can try grounding the lights, at least the tail lights to the ground on the plug.

Not the best drawing but I'm assuming that this is how it's wired

1223b39200bb306f7b87d4fd7555619c.jpg

Try running all the grounds to the plug. Bypassing using the trailer as a ground

d706ae008b234f1030754b0059443033.jpg


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NateTheGreat

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The grounds for the lights are in the mounting hardware.

It just seems silly, shouldn't all this be standardized? Why would it work perfectly on a different make if it were a ground issue?
 

1500ram12

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I understand but I think it's a ground issue. Could just be something with your truck. If you know anyone else with a ram have them hook up and see if it works on theirs


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csuder99

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I'm with the "ground" crew ;) The symptoms sound like the lights are getting ground through the trailer hitch instead of the connector. Either the connector ground on the RAM is bad and works on the Chevy, or the hitch on the Chevy provides a better ground than the newer RAM (paint etc.)
 

gofishn

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IIf I understand correctly, everything functions properly except left side and runing lights whivch would include the left side.

If so, am thinking left side bulb is faulty or Ground is bad.

Pleas, let us know what you find.
 
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