Harness sealing liquid

good afternoon, I was hoping that you could help. I need to build a harness for in my off-road truck which will need to be sealed to prevent water ingress by capillary action.

Is there a liquid on the market that will allow me to do this that would seal but remain malleable.

Many thanks in advance

Resintech RT125 is what most use. Adhesive lined heat shrink boots on the backshells and junctions will stop the rest.