Can't you use just regular 30/40 amp bosch relays and then take some heat shrink tubing like 2" wide and wrap them down over the harness? When you do this correctly it should make them 100% water proof. I have never ran accross sealed relay's. If a relay switch is something totally different then I have never even dealt with those. But you can find bosch relays or potter and brumfield relays at most any local car audio shop. These are the better ones to get by the quality of material used in them. They shouldn't cost you more than $6 each tops with a relay socket harness. The heat shrink might add a bit more but you can probably find some at the home depot or an electrical supply store.