The reason why it does not work with every 4s is simply the car itself namely on 2 things.:
1 is a cigarette lighter in the car each and a car port installed? Then please in the specially Car Connection
2. is "only" installed a cigarette lighter? Then you probably light, wipers, ventilation and a 100Watt car run on radio simultaneously. Just 5-minute drive, and a disconnect and it works.
Did it even so found out at 4 different cars.
The part 1a, only through the retractor wears out the part with extensive use sometimes like in 6 months. This is at the price but through out all right
