9004 vs. 9007 Headlight Wiring Differences

9004 and 9007 bulbs have different ground, low-beam and high-beam terminal positions. Check the correct wiring before installing HID or replacement headlight bulbs.

Problem

When I turn on the low beams, the headlights do not turn on.

Solution

Check that the ground and power connections are in the correct positions for your bulb. On some HID and halogen combination bulbs, the two wires running to the bulb base are ground wires.

9004 and 9007 wiring diagram

View of the three terminals in the same orientation as the SMD reference diagram. Confirm the socket orientation before working on your vehicle.

Quick comparison

Important: Do not connect the wires by color alone or assume that 9004 and 9007 are interchangeable. Turn off the power and verify the vehicle wiring and bulb pinout before making changes.