Help finding a short in a tail light assembly

[fxdls110]

Hello, everyone.
First off, I will state that while I have reasonably decent soldering skills, know my way around a multimeter, and can identify most simple components, such as resistors, capacitors, diodes and transistors, my diagnostic ability leaves a lot to be desired.

What I have is an aftermarket, integrated tail light assembly for a Harley Davidson. This has the tail light, brake light, left and right turn signals all in one, small package.
A friend of mine and I were on the road when we were hit with some of the worst torrential downpour weve ever ridden in.
Long story short, the light assembly got a bit wet within the housing. Now, all of the individual lights DO work, however, the lights that are supposed to be on for the "tail light" function do not come on, and only come on during the "brake light" function, which is when the same lights just become brighter when the brake switch is applied, if that makes sense.
I have cleaned all of the water marks off of the board as best as I can, and cannot seem to find the source of the interruption of power that is preventing the tail lights from coming on, so I am wondering if someone who is much more proficient could perhaps point me where to look.

 

[Nigel Goodwin]

Water gets everywhere, and it's VERY difficult to repair water damage, and if you do it tends to be unreliable.

But there will be water under pretty well every component on the board, and could even be inside the board as well, it's all sat there corroding away.

Assuming you want to try and repair it?, for a start take every component off the board, and clean the board thoroughly with solvent - IPA or something similar. Then clean every component in a similar way and refit them - then cross your fingers.

If you have access to an ultrasonic cleaner?, you might try using that (full of IPA) to see if that can help.

 

[fxdls110]

Oh, so in this case, the water is likely in between the laminated layers of board as well. Good to know. Im not too keen on rebuilding the entire thing, honestly. I was able to contact the company this morning, and they acknowledged that this is a known issue, and, since the light carries a lifetime warranty, the rep has sent me a replacement.
That said, I wouldnt mind trying to fix it anyway. Thank you for telling me how much of a challenge this will be. Strangest thing is that every function of the light works as intended, just not the tail light function. The strip of lights in the top of the left picture I posted are the license plate lights, and they come on at all times like the tail light, and they do work. I kind of wonder if there is water beneath that black, rubbery substance they put where the wires attach to the board as well? Seemed to me that it was water tight, but after what you said, all bets are off in my mind.