opel astra h 2006 dosnt start unless open switch...

To solve the problem in your car opel astra 2006 : 
1. Check the battary : if teres no click on starter that's mean dead battary ,if you can hear clicking, it may be because the starter is attempting to work but does not have enough power.
If the engine is turning over but won’t start, it likely isn’t an issue with the battery
Check the voltage of battary it must be between 12.4 to 12.7 volt
2. Check the pole of battary
3. Check the starter
4. Check all fuse
5. Check the crank sensor
6. Check the fuel and filter pump
As shown in video Video link