Lighted bathroom cabinet/mirror fault.

My guess is that the door has two pivots - one at the top and one at the bottom. The current reaches the door via the pivots acting as the two conductors.

Use a voltmeter to find if there is an AC or DC voltage between the pivots. If there is, the door is at fault. If there isn't, the cabinet is at fault.

Or those pivots are tubes, and have wires passing through them? I checked mine and it has a very obvious wire passing from the chassis to the door.

Thankyou, that is so obvious now that you have pointed it out. I thought it must be something like the no-contact phone/toothbrush chargers. I'll check it out tomorrow. Thanks.

On inspection, there is voltage to the LED driver. That is fed from an IR sensor switch. The outgoing supply, presumably 12v DC is fluctuating, so I cant get an accurate reading on my voltmeter. I'm not sure if that is a fault on the driver, or a product of switch mode power supplies. Either way, a new driver is cheap, so I'll get a new one and try it out.

A lot of those cabinets use hidden contact points or hinge-based connections rather than visible wires. Power is often transferred through small metal contacts in the hinges when the door is closed.

If the shaver socket still works, it could be an issue with those contacts or the LED driver inside the door. Sometimes the contacts get dirty or misaligned, so it might be worth checking the hinges closely.

A lot of those cabinets use hidden contact points or hinge-based connections rather than visible wires. Power is often transferred through small metal contacts in the hinges when the door is closed.

If the shaver socket still works, it could be an issue with those contacts or the LED driver inside the door. Sometimes the contacts get dirty or misaligned, so it might be worth checking the hinges closely.

Are the fluctations seen on digital meter or a mechanical one? If digital, the switching frequencies of the meter and the cabinet will beat with each other. A mechanical meter has so much inertia in the movement that it should ignore any high frequencies in the voltage. However if the needle still fluctuates in the same way, there might be something funny with the driver.

Perhaps you could wire a small incandescent bulb between the two contacts to see if it loads the circuit and lights up steadily.