After installing a set of H4 hid headlights after turn on the light side of the bright side and not lit but the HI / LO, what causes?

You want to know this reason, the let FUCHW to explain it to you.

Principle: the reason is that the ground (negative) Poor Ground cord poor contact or power input plug inserted backwards.

Solution: anti-insert the plug over to solve the problem.

Guangzhou Fuchw Industrial Co., LTD. it is specialized in manufacturing and exporting of hid headlights ,Manufacturer hid,auto led bulb ,auto halogen bulb