Interior trailer lighting gremlin .

[huntandjeep]

First I hate wiring and here is why. Bought a used snowmobile trailer and sleds and spent the day cleaning it up and going over things . It has the clear oval Semi lights you see on tractor trailers inside . 2 passenger side and  2 drivers side . Previous owner said it needs 2 new lights as 2 of the 4 are burned out ( drivers side burned out ) . Found 2 spares  in the trailer and put them in , No lights . Dummy wired the spare lights to my Jeep battery and they both work ( tried the 2 " burned out " ones and they work when wired straight to the Jeep  battery also )  Pulled the 2 working lights from the passenger side and put them in the drivers side  , nothing . Bought a test light to start tracing wires and the Pigtails for the 2 "  burned out " lights have power to them . Only the 2 currently working lights will work on the passenger side . If I try the spares or the " burned out " lights in the passenger side none of those will work in the passenger side spots .

 So I have 6 working lights ( 4 hooked up in the trailer and 2 spares ) , 4 pigtails that are hot and yet only the 2 lights on the passenger side will work . No combination of lights will work on the drivers side , and only the 2 that are currently working on the passenger side will work there , none of the other 4 will work. Anybody have any ideas , because this is making no sense at all .

  I'm 90% sure the interior lighting , exhaust fan and plug all run off a 12v car battery .

[getreal711]

The 2 lights that don't work but have  power. Make sure they have a ground. No ground and all the power in the world won't light them. Even slave in a ground to try them.

[huntandjeep]

The 2 lights that don't work but have  power. Make sure they have a ground. No ground and all the power in the world won't light them. Even slave in a ground to try them.

The pigtail on the trailer consists of 2 male prongs , The light has females , 1 labeled " Source " the other " Ground " . When I hook the Alligator clip of my test light to " Ground " and probe the " Source " the test light lights up ? Doesn't that mean it's grounded ?

[Crunchy]

I would guess ground as well.  If you had a short you would have likely blown a fuse.

[Boss .300 winmag]

The 2 lights that don't work but have  power. Make sure they have a ground. No ground and all the power in the world won't light them. Even slave in a ground to try them.

Do this first, it lights light up you know it’s a ground problem, and now you will know the rest of the story.😉

Your ground wire, or plug is jacked up.👍

[the1rod]

The 2 lights that don't work but have  power. Make sure they have a ground. No ground and all the power in the world won't light them. Even slave in a ground to try them.

The pigtail on the trailer consists of 2 male prongs , The light has females , 1 labeled " Source " the other " Ground " . When I hook the Alligator clip of my test light to " Ground " and probe the " Source " the test light lights up ? Doesn't that mean it's grounded ?

The means that you have power and ground at you're plug.  And if the light has proven to work,  then hooking it to the plugs should work. But there are a few possibilities.  One,  hook to a separate ground source and test the connectors and make sure they aren't labeled backwards.  Also is your test light led or standard bulb? A led test light will light up with very little power which might not be enough to light up the trailer lights.

[huntandjeep]

Its an LED test light which makes sense as it takes less to light it up . I will re- ground all the pigtails tomorrow and report back .

[Cougartail]

Remember.. The power flows out of the negative side of the battery then comes back to the positive side. this is why you always check for good grounds in 12v systems.

[Russ McDonald]

Remember.. The power flows out of the negative side of the battery then comes back to the positive side. this is why you always check for good grounds in 12v systems.

Power or current flows from a battery  from positive to negative.  Current is the electricty.  It is electrons that flow from negative to positive.  That being said in any lower voltage system the ground is a big thing.  If it is bad or flakey you will have issues for sure.

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[Caseknife]

Use an 1157 bulb in a socket with pigtail for your test light, that will put a good load on your circuitry.  If the lights that are in the trailer are LED, they are directional and won't work if hooked up backwards.

[Mark Brenckle]

Use an 1157 bulb in a socket with pigtail for your test light, that will put a good load on your circuitry.  If the lights that are in the trailer are LED, they are directional and won't work if hooked up backwards.

    Keep your test light grounded to the same point and test each lead of the side that works and the side that doesn't. Label all the positive wires. Then hook your test light to the positive side and confirm your grounds.

[huntandjeep]

You guys called it . It was a ground problem.  The builders decided to pop rivet the ground to a section of trim . Ran the  grounds straight to the trailer frame and everything works as should . Thanks

[Cougartail]

Remember.. The power flows out of the negative side of the battery then comes back to the positive side. this is why you always check for good grounds in 12v systems.

Power or current flows from a battery  from positive to negative.  Current is the electricty.  It is electrons that flow from negative to positive.  That being said in any lower voltage system the ground is a big thing.  If it is bad or flakey you will have issues for sure.

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Current is the flow of electrons. Motion, heat, and light are the three types of energy. Opposites attract and since the electrons are negatively charged they move to the positive terminal. The internal workings of the battery sets up a deficit of electrons on the positive side and excess on the negative side causing pressure, thus inducing the flow (Current). The only time this doesn't happen is when a separate power source exerts a greater pressure i.e. a car alternator. The alternator through chemical reactions resets the imbalance.

[getreal711]

Glad we could help. We can bill you later for the consult fee.

[the1rod]

You guys called it . It was a ground problem.  The builders decided to pop rivet the ground to a section of trim . Ran the  grounds straight to the trailer frame and everything works as should . Thanks