Are you upgrading your headlights to HID or LED and running into problems—such as only one side lighting up or the lights not turning on at all? This is a very common issue on vehicles that use H4 / 9003 / HB2 bulbs. This adapter acts as a ground-switching module, providing a true plug-and-play fix. It’s designed to work with most cars, trucks, and SUVs that rely on an H4/9003/HB2 headlight connector with a switching ground setup for low and high beam operation. Installation These polarity converters simply plug in between your vehicle’s factory H4/9003/HB2 socket and your aftermarket HID or LED bulbs. Once installed, your upgraded headlights will function just like the original halogen setup. What’s Included 1 pair of polarity/ground adapters Compatibility Works with ground switched vehicles that use H4, 9003, or HB2 bulbs. Compatible with older Toyota, Subarus, etc, using H4 ground / negatively switched systems. Used with LED projectors such as our NHK or S8 series projectors that are pre-pinned for H4. Not to be used with a H4 relayed wiring harness.
