Puzzled by Trailer Lights

[Jogeephus]

Was checking the trailer over this afternoon. Wanted everything in good order for the morning. Right rear light was not working - brake, blinker nor running light. Checked fuses first - Ok. Checked bulb - OK but put another in anyway. Got a tester and tested wire - it has power. Touched tester in socket and it shows I have power. Touch side of socket it is powered up as well - don't really know if this is supposed to be happening though. Cleaned connecters in socket. Still can't get bulb to light up. Any ideas of what to do would greatly be appreciated!!! Thanks in advance. (Oh, any ideas other than buying a new truck and trailer.) :lol:

 

[Alice]

Was checking the trailer over this afternoon. Wanted everything in good order for the morning. Right rear light was not working - brake, blinker nor running light. Checked fuses first - Ok. Checked bulb - OK but put another in anyway. Got a tester and tested wire - it has power. Touched tester in socket and it shows I have power. Touch side of socket it is powered up as well - don't really know if this is supposed to be happening though. Cleaned connecters in socket. Still can't get bulb to light up. Any ideas of what to do would greatly be appreciated!!! Thanks in advance. (Oh, any ideas other than buying a new truck and trailer.) :lol:

Drive over a big bump...always works for my brother.

Alice

 

[Mahoney Pursley Ranch]

Sounds like the bulb when in the socket is not making contact with the socket prongs.

 

[dj]

You can get power off the socket? Thats not right. The socket should be the ground. Look on the back side of the pigtail insulator to see if a wire is bare and touching the spring.

 

[Jogeephus]

You can get power off the socket? Thats not right. The socket should be the ground. Look on the back side of the pigtail insulator to see if a wire is bare and touching the spring.

I thought that might not be right but I didn't think to test the other one to see if it was doing it. Unfortunately, the light is riveted in place and I'm probably going to have to remove the whole light to get a look. If I do this, I will probably end up sticking a new fixture in here.

I checked the bulb and it feel like it is making contact with the thingamajigs. There is a spring behind it and I can feel pressure when I'm putting the bulb in.

The problem has got to be in the last 5 inches of wire - that which I cannot see. I'm leaning toward what you suspect - a bare wire. But this one has stumped me so far!

 

[backhoeboogie]

It is your ground. I suspect the bolting for the housing is not grounding to the trailer. If you have power to the light based on a tester (that is grounded by the way) and your bulb doesn't illuminate, it is not grounded. Not only do you have to have power, you have to have a ground.

Most trailer light fixtures are self grounded to the trailer. You may have an internal wire and you may not. If you do, the internal ground wire may be shot. Make yourself a small jumper and jumper a ground from the trailer to the light base socket base. If your light works you can leave that jumper until you get time to replace the problem.

 

[MillIronQH]

Might be cheaper to just move to Texas where a little thing like lights on the trailer is a non-issue (plates either for that matter). ;-) Z

 

[Saltydawg]

Like Backhoeboogie already said it's your ground.

You are reading positive voltage through the outer side of the socket cause the ground is bad and you're getting feedback through the other lighting circuits.
It's tough to explain but thats what it is.

Follow your ground circuit and you'll find the problem.

 

[longhorn314]

I would think it would be your ground to.I don't know how many times I have had to fix trailer lights and I always check the ground.

 

[eric]

You have a trailer with at least one working light??

Braggart!

 

[sidney411]

It seems like every time I hook up a trailer there is at least one light that doesn't work. Murphy's law I guess.

 

[Saltydawg]

I got tired of hooking up to other people's trailers or old equipment and not having the lights work so I went and bought one of those magnetic sets of tailights.

They are tail lights that have a magnetic base and about a 20ft or so lead wire with a trailer plug.
You just plug it in to your tow vehicle which should have a good harness and trailer light plug on it and then stick those tailights to the back of whatever you're towing.
It won't get you lots of fancy side marker lights but it will keep you legal towing those "less than perfect" pieces of equipment around.

http://www.pplmotorhomes.com/parts/rv-l ... lights.htm

 

[Jogeephus]

You have a trailer with at least one working light??

Braggart!

Yeah, used to if you had all your lights working they would pull you over thinking you were hauling drugs or something. Now local gov'ts are strapped for cash and are cracking down. Don't need a ticket.

Thanks everyone, I got it fixed. It was the ground. In the one place I didn't look. In the plug on the truck. One of the fins was not making a good connection. Bent it a little and the world lit up. Think I'm gonna hafta buy a new plug for the trailer though. Its got too much play in it. Thanks again. My needle got stuck on this and it almost got the best of me.