Originally Posted by
Rob M
... the seller placed a bead of silicone sealant around the edge of the cover after doing the refurb and even though it would be trivial to cut through the sealant, I think I'm just going to leave it closed up.
The box the RCM/BCM/PTCM sit in is force-air-vented with cabin air. This keeps temperatures under control in the box - but it also helps keep air moving to move moisture.
IMO, (after 31 years in electronic troubleshooting) sealing the RCM is a bad idea. I suspect the seller (or someone) thought they were sealing out contaminations that might pit the relay contacts, but IMO this is not a good idea.