1. You may have a brake switch going bad. You can pickup one from most auto part stores. Part # 25771554. Usually less than $20.
2. The noise you hear is Hydro Boost working. It is normal when engine is not running. When engine is running power steering pump provides the boost.
3. Had a similar problem on my Endura recently. Found that ground wire for all rear lights had broken off. Replaced wire and hooked back up to frame. Some Kodiak's have fuses instead of circuit breakers. There is also a separate relay for brake lights. Fuses are under dash panel on passenger side of dash. Need a 10mm wrench to remove screws. Do you have running lights at back?
4. If you have a brake controller hooked up on your MH. It may not be wired properly. On the Kodiak brake controller should be hooked to the light blue wire in the wire harness called out in
Bulletin 66. The wires called out in Bulletin 66 can be found on inside of passenger frame. Look on frame near end of cab. This can also be reason for brake switch failure in item 1 above.