Why doesn’t my bicycle headlight switch off/on with the light button?

If the headlight on your Helkama bicycle doesn’t turn on using the light button, your bike likely has an automatic dusk sensor light. The dusk sensor light switches itself on and off depending on the brightness of the surroundings. On a bike equipped with a dusk sensor light, the daytime running light and rear light are always on when the bike’s power is switched on.

If the headlight stays on constantly, it’s probably because the environment is dark enough for the light to activate. This is typical indoors. The dusk sensor is designed to be sensitive enough to turn on the light in conditions like rain or fog.

You can test the dusk sensor light by shining a torch beam directly at the rear of the headlight, where the dusk sensor is located (see the picture next to this text). If you illuminate the dusk sensor, the light will switch off. If you want to test whether the light turns on in a bright environment, you can cover the dusk sensor with your hand.

If none of the above works, or if the headlight still doesn’t respond, or no light comes on at all, you should have your bicycle checked at a professional service shop. You can find authorised warranty service shops using our dealer search.