update:
Replaced the actuator 6 months ago due to the relay clicking, new from nissan.
All fine until a month or so ago, clicking stated up again, but only on hot days and only after driving for more than approx 30min. And even then, doesnt always happen, maybe on 1/3 of long drives. The clicking occurs rapidly on accel and when snow button is pressed whilst idling. If I turn off/on engine for a few minutes it come good. This all matches the pattern i had before i replaced accuator. I would have thought if actuator went, it wouldnt be an intermittent problem, but always ? For those who fixed theirs with actuator, was it clicking at all times ?
Not keen to spend another $350 on a new actuator.
It appears heat related, possibly pump or electrical ? Any ideas. And yes, new fluid, bled many times from both nipples...