Two things come to mind on moisture ingress. These remotes (I have 2 in service) can be considered outdoor electrical boxes, and subject to the same sealing, heating and cooling effects.
First, I slather the two mounting points with silicon lube on the threads and all over the outside.
Second, the parting line between the cover and the bottom plate slowly opens over time. Another good place for grease.
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Temperature and humidity changes will draw moisture thru the smallest openings. Seems like they never effectively act as drains, though. The tuner's board is up off the bottom but, if water can pool there, it'll hold the interior at high humidity. A non-sealed board and parts will magically become hydrophillic.
If cleaning the visible ares, and not finding signs of corroded off clads, there may be internal damage to the relays.
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I mount mine so that a 5 gallon joint compound bucket can be dropped over the top.
If I were to experience what you did, I stick an electrical box vent and a low weep hole in the housing.
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Mike N3PM
