2005 Vauxhall Astra Car Hazard Lights

2005 Vauxhall Astra 16000 miles

Hi,

Up until 2-3 weeks ago, whenever I charge my phone or sat nav in my car my hazard lights come on.

When I take the hazard lights off, the light on the charger or sat nav comes off. It's as if there is a problem with wires or something?

Do you have any idea what this could be? I will take the car to a garage next week for diagnostics.

Thanks
Anty