Have a 2007 Fabia II 1.4 tdi, trim '3'  

 

Front sidelights  - sometimes - only one of them comes on. One time only driver's side was on before starting the engine, but then with engine running both were on. Any ideas what could cause this? 

 

Thanks

 

 

Dodgy bulb? Try swapping them round. So drivers side is on the passenger side and vice versa