hello guys i have skoda octavia 2 year 2007 model,i bought one android navigation stereo system which is called name as columbus i tried to fit this everything works except sound, there is no sound coming from any speaker,we tried this in another skoda car which is older model and the sounds works,the only difference in my cars that i have premium speakers in my car and an extra amplifier under the seat which is from the company built in,,,, any solution please help thanks 🙏 

you will need to disconnect the battery with the stereo removed, then install the stereo again. This should force the factory amp to switch on with ignition instead of being woken by canbus signal from the stereo.

thanks 🙏 man you mean the car’s battery ?

and one more thing should i install the stereo before battery attach or after ?