[CaptainGizmo]

One of our fantastic fans needs an occasional twist of the raising/lowering knob to give it a boost to start going up.
The fan works great once the lid raises.  And lowering, and shutting off, is no problem.

I’m not sure how the lid motor shuts off; whether it’s resistance or a micro-switch, but my inclination is to go after that gearbox and see if it needs a bit of contact cleaner.

Anyone have this happen, and find out the root cause?

[hbens]

Steve,
Once I replaced just the manual knob you pull down on and then twist left or right to open or close the vent. It was much less expensive than the whole fan.
That was faulty so I put the old one back in and replaced the lift lever. It worked for a while and then went back to trying to open or close forever. I replaced the whole fan then.
http://newellgurus.com/showthread.php?tid=6819 Here is the thread on that replacement.

[hypoxia]

Here's the wiring for the 3350.  I believe the motor stops with a load and is controlled by the circuit board.  The lid lift is a worm drive.  Although the motor may be the problem I suspect the circuit board.  Call Fantastic Vent, they used to have great customer service even after Lippert bought them.

[CaptainGizmo]

Thanks Jim, I think your description is how the drive works on mine.

I’ll try to call and see what they say.