I've just spent an hour pairing my Trådfri dimmer kit (104.359.26) with my Philips Hue bridge after the dimmer became unpaired from the bulb a few days ago (first time this has happened since I first installed the kit about a year ago). I was having issues following the existing guides, so I figured I would write down the procedure that finally worked, mainly for my own future reference, but also anyone else interested. For reference, the product numbers of the contents of my kit appear to be 704.085.95 for the dimmer and 904.087.97 for the dimmable bulb.
Note that you cannot see or control the dimmer from the Hue bridge, but this procedure allows you to use both the dimmer and the Hue app to control the bulb at the same time.
- Install and set up the Hue Essentials app. Then tap the plus button on the devices tab and select Smart control > Other.
- Physically unplug all lights and turn off all switches to avoid accidentally pairing the wrong bulb. You might need to turn a few of them back on before step 7 in case your bulb is too far from the bridge and needs the signal from other bulbs to reach the new bulb. You could also temporarily move the new bulb closer to the bridge (same room should be more than close enough) while pairing.
- Turn on the Trådfri dimmable bulb, then reset it by quickly flicking its power 6 times. After the 6th time it is turned on, it will blink a few times to inform you it is reset. Leave it switched on.
- Reset the Trådfri wireless dimmer by unscrewing its back cover and quickly pressing its link button 4 times. A red light on the dimmer will blink 4 times to inform you it is reset.
- Place the dimmer on top of the Hue Bridge. While holding down the dimmer's link button, quickly press the Touchlink button in the Hue Essentials app. Wait a few seconds until the red light stops blinking, then release the link button on the dimmer.
- Hold the dimmer right next to the bulb while pressing its link button. The bulb will start blinking for about 10 seconds. Release the link button after the bulb stops blinking and switches to max brightness. Check that you can control the bulb with the dimmer.
- Flick the power for the bulb once (I flicked it 3 times, but it should be the same). Then quickly use the Search for lights button in the Hue Essentials app. After a few seconds you should get a message informing you the bulb was found and connected.
- Use the official Hue app to add the new bulb to a room (open a room, press the Add Lights button and tick Unassigned bulbs). Test that you can control the light using both the Trådfri dimmer and the Hue app.
A similar procedure should work for other Trådfri products, but their functionality might be a bit limited. I also have a Trådfri remote control kit (204.065.70) with the old remote model (104.607.51) and a dimmable white spectrum bulb (404.867.83) where I can control the color with the remote, but it always gets out of sync with the setting from the Hue app. I also had to reset that kit a few days ago, but forgot the steps before I could write them down (they were pretty much the same as what I wrote here).
Edit: After writing this guide I realised my remote control kit became unpaired and I could no longer control my other Trådfri bulb with the control kit, only the Hue app. Since the bulb was already correctly paired to the bridge (using the steps above), I could fix its connection by following the same steps as above for pairing the remote skipping the bulb setup in steps 3, 7 and 8. I have now tested that both of the kits are correctly paired at the same time.
Update: Not even 4 months later the Trådfri E1810 remote unpaired itself again. I could reconnect it by following the steps 2 and 4-6 above (i.e. skipping 3, 7 and 8, same as before), but this is incredibly annoying, and I wouldn't recommend buying the remote control kit. I've had zero communication issues with Hue devices in the same time, and this Trådfri remote control kit is the closest to my hub out of all my devices.