depending on the connector...Dielectric grease can cause issues of it's own... for the most part... it is good to use.... there are also different dielectric greases.
A non-sealed relay (the actual case of the relay.... not the connector)... is not good at all, if truly not sealed. A non sealed relay... even in a 'bag' with the electrical stuff... IMO... is just waiting to fail from all of the humidity and condensation that happens in these sleds from normal use.
Thats why I'd like to see some high resolution photos of the relay itself and it's markings... also to know the resistance of the stock relay between post 85 & 86.
As for the relay and ordering.... need to match, fairly closely, the resistance of the trigger coil in the relay.
As for the engineers on these sleds at Polaris... I've met them and know a few of them... they are not 'corner cutters'.... that is where production costs and the staff at Medina get in there... and reign-in the engineers and their abilities to make a great sled and fix what really is a 'fixable' issue of the sub par wiring and component integration, IMO, on these sleds.
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Plasti dip or brush on electrical tape will make them water proof. It's not the cure but it is a long lasting fix