Electrical Short in Exterior Trailer 7-Pin Lighting Circuits

[JonDarling]

Recently noted that my running lights started flashing with my right turn signal. Upon further debug I isolated the short to the
right rear "sealed" tail light fixture (made by Optronics). The unit appears to have taken on moisture and was 1/4 full and ohmed
out as a direct short between the 7-pin running lights pin and the Right STOP/TURN pin. What's not clear is why this fixture which
was reportedly "sealed" took on water and I'm wondering if the placement directly below the hot water heater had any role to play.

My Nissan Titan seemed to tolerate the short while making the trailer look like a Christmas tree when making right-hand turns but
it eventually stopped working all together and I lost all trailer running lights and STOP/TURN signaling - NOT GOOD.

Love to know if other's have seen this issue and if the answer is to simply buy a replacement fixture. Comments welcome.

[TucsonJim]

Nice trouble-shooting Jon. I had another brand that mounted the moisture drain holes on top. It completely filled with rain water....

Jim

[Scott'n'Wendy]

I have not had that happen to me...yet...but I would think replacement is your only option. LED lights usually mount with a small cct board in there and it is likely corroded.

You could forensically disassemble the unit for interest....

[familytruckster4]

Its common for those to leak. I replaced mine about 6 months in after I found water in them during the first long trip. If I recall they looked like they were sealed but leaked like a sieve. I initially drilled a very small drain hole in the bottom of the lamp. It was a good excuse to upgrade mine to bigger units.
I learned when diagnosing similar issues on the trucks at work to start with the brake/tail light first and work forward. There are a number of issues that could cause this but for me that always had the highest success rate for finding the fault.