When you have the lights switched on and close the hood are the lights going off?
no - but they never have.the lights have always been independent of hood position.
when i try and switch on the motor there is a faint hum that is definitely related to moving the switch away from 0 but nothing else happens. (hadn't noticed this before original query)
Ok couldn't remember if the lights was on the switch as well as the motors on this model.
There is a micro switch on the right hand side of the hood were it goes into the appliance itself. You will see a small plastic cover. Remove this and there you will see a microswitch with a small lever. So when you pull the hood it activates the switch to allow the motors to run.
Check that switch and see what you find. As there are no fuses in there which control just the motors.
Let me know what you find.
I can't see a separate microswitch on either side. There are red plastic toggles on both sides connected to springy, metallic fingers. The red plastic toggle won't separate or I'm being kack handed trying to do it.
I tried an alternative to get a feel for whether the microswitch is working
Starting with the hood open and fan switched to 0 there is no sound and the lights operate on and off as commanded. Switching the fan on with the slider switch and leaving the fan set to 3 there is a gentle hum. Shutting the hood stops the hum.
Checked same result with my son's 20 year old ears. Is the microswitch set in part of the metallic finger? If so I'll try and prise it off.
I'm trying to avoid taking the hood out all together. The small gap and presence of ducting to outside prevent access to the motor and fans from above.
Sorry for the delay.
If you hear a hum with the hood open but stops when you close it then the microswitch is working so we can leave that.
What this sounds like if theres a hum is the capacitor. As the motors get a kick start by this capacitor so if this is faulty the motors cannot run so they just hum.
To access this you need to remove the pull out hood.
Now from memory you need to pull open and then lift or twist them as this will allow the hood section to pull out and you can then remove it.
Then with this out you can see a plastic box in the right corner looking at the diagrame. Remove this and the capacitor is in there. Its a sliver or white cylinder with a few wires on it. Replace that and then refit the hood and this will cure the fault here.