1.both side could not work?
please turn around the plug (swap the polarity) and try again
2.One side could not work?
3.both side flicker/interference/error light?
Pls kindly noted that your car need a resistor Cancelers Decoders, you can contact our customer service for help
4.My bulb type is H7, but the one you sent could not fit?
Pls kindly noted that your car need a bulb holder to lock the bulb, you can get one from ebay according to you vehicle model
5.My bulb type is H1, but there is only one clip on my bulb and the one you sent has two clip
Pls kindly noted that different cars have different connection way, which some have both positive and negative electrode, while some just have positive electrode but not negative. if there is just positive electrode but not negative, please connect the positive side, as for the negative wire, please connect to the car's metal shell.
6.the bulbs is loss and it could not fit(H8/H9/H11/9005)
Please put the bulb in the bulb assembly, and make sure to rotate the bulbs in the socket by clockwise, only by this way can install the bulbs, if you just put it in the socket, cannot stable the bulbs.
7.the bottom of the bulb is too big and it could not fit
For some special cars, you need to make a hole on the waterproof/dust cover and let the fans come out, and in this way will solve the radiating problem.