minor trailer light issue

[kchaudha]

I know there are tons of posts/articles on trailer lights but figured this might be worth asking specifically to see if anyone can suggest a quick fix/thing to check:
-signals and brake lights work fine.
-Running lights only work on left side.  Does not work on trailer right side
From what I have read, it sounds like this could be a ground wire issue?
Taking a look at the actual light on the right side, I see that it is wires with a mini 4-way harness.  I haven't dug beyond that to see what else may be the issue.  Looks like only one bulb in the lamp so I guess it can't be a blown bulb if the other functions are working.
Any suggestions?

[John Jones]

Normally the bulb is a dual element bulb.  One for the run lights and one for the brake/turn and the brake/turn element should burn brighter.

-bad bulb
-corroded bulb
-corroded socket
-wire broken internally
-corroded splice
-corroded ground if it's connected to trailer frame

(I can probably think of more    )

[kchaudha]

Ah - didn't realize that - could be the bulb then.  Better check that first...

[kchaudha]

Normally the bulb is a dual element bulb.  One for the run lights and one for the brake/turn and the brake/turn element should burn brighter.

-bad bulb
-corroded bulb
-corroded socket
-wire broken internally
-corroded splice
-corroded ground if it's connected to trailer frame

(I can probably think of more    )

Opened it up and checked it out.  Bulb "looks" fine..  Everything else looks ok too... maybe worth trying to change the bulb anyway though? Ground was fine but I cleaned it up anyway and the running lights still don't work.  Brake and signal still work though.
I guess the bulb filament could be bad even though it looks ok?  This is the Wesbar "waterproof sealed unit so I have to break it open or change the bulb if I want to replace.

[John Jones]

The Wesbar elements aren't cheap.  I would try to find a way to hook 12v directly to the element before buying one.  

There should be a brown wire for the running light and ground is normally black.  I have a Wesbar element somewhere in the garage.  Let me go look at it.

[John Jones]

Okay.  The Wesbar capsule that I have is number 3348.  I bought it about 10 years ago for a trailer that I no longer have.
Red wire is brake/turn signal.
Black wire is running light.
White is ground.

The colors I gave above are for standard trailer wiring harnesses.


Here is the one I have.
http://www.easternmarine.com/wesbar-sea ... psule-3348

You can have it if it will fit.  The package is falling apart but it's new.  If you want it PM me your shipping address.

[John Jones]

Standard US trailer wiring color code.

[kchaudha]

Okay.  The Wesbar capsule that I have is number 3348.  I bought it about 10 years ago for a trailer that I no longer have.
Red wire is brake/turn signal.
Black wire is running light.
White is ground.

The colors I gave above are for standard trailer wiring harnesses.


Here is the one I have.
http://www.easternmarine.com/wesbar-sea ... psule-3348

You can have it if it will fit.  The package is falling apart but it's new.  If you want it PM me your shipping address.

Awesome thanks!  PM sent.

[kchaudha]

John - thanks again for sending me the bulb.   I changed it out today and really thought it would solve the issue... but unfortunately the same symptom remains.  Seems really weird...as I guess all trailer light issues are...
-signal works fine
-brake works fine
-running light still does not work!
-ground wire seems firmly attached.  If I disconnect it from the frame, the signal light doesn't work anymore.  When connected to frame, the signal works but running light doesn't/
Does this make any sense?  Why would the running light not work when the signal works on the same light?
Any other thoughts?

[John Jones]

Check the wires coming out of the light.  Black Wesbar wire connects to what should be a brown trailer harness wire.  Somewhere between the black wire and the plug up front is a bad/open/corroded connection.

[kchaudha]

Got it - slightly corroded connection near the light.  Thanks for all your help.
The lamp also was useful.  There is one big bulb and one small bulb in these capsules.  My small bulb was completely burnt out so this new one is perfect.
These lights were certainly worth playing around with and now I know so much more for how to troubleshoot wiring for the next time.
Many thanks!

[John Jones]

Glad it worked out for you.