The Electrician #1: How to Fix a Pull-cord Switch
How to fix a stuck or faulty bathroom pull-cord light switch.
Important
Introducing: "The Electrician" series
AI may soon automate much of a Software/ML Engineer's work. "The Electrician" series features tutorials on fixing things around the house—my humble Plan B for the post-AGI economy :)
In the UK, it is common to have a pull-cord switch for bathroom lighting. Unfortunately, it is also common for these switches to get stuck, stiff, or unresponsive after a few years of use.
In this tutorial, I will show you how to fix a stuck switch simply and effectively.
Step 0: Isolate the Circuit (Safety First!)
Before doing anything, find your fuse box (consumer unit) and turn off the electricity to the lighting circuit.
IMPORTANT: ISOLATE THE CIRCUIT
Double Check: Use a Voltage Detector Pen to verify that the power is definitely off. Never assume the circuit is dead - always check!
Step 1: Remove the Switch Housing
Carefully unscrew the switch box from the ceiling.
Crucial: Take a photo or note the exact position of the wires before disconnecting anything. You will need this to reconnect them correctly later.
Step 1
Step 2: Open the Mechanism Box
Open the internal casing to expose the switch mechanism.
Step 2
Step 3: Lubricate with WD-40
Spray a good amount of WD-40 onto the base and housing of the switch mechanism. Ensure the lubricant penetrates the moving parts.
Step 3
Tip
What is WD-40?
WD-40 is a water-displacing spray, lubricant, and cleaner. It is a petroleum-based product used to prevent rust and corrosion, and to lubricate moving parts.
You can find it in almost any hardware store or on Amazon.
Step 4: Clean and Dry
Use a cloth to wipe off any excess liquid and let it dry for a few minutes. Operate the mechanism manually a few times to ensure it moves freely.
Step 5: Reassemble
Put the mechanism back into its casing and reconnect the wires to the switch, ensuring they match your photo from Step 1.
Note: In my specific case, the Brown (Live) wire went to the left terminal (often labelled COM), and the Blue wire went to the right. Your wiring may differ, so always rely on your own notes.
Screw the unit back onto the ceiling, turn on the circuit, and you're done!