Low Beam Not Working Due to Damaged Wiring Harness

The headlight on the passenger side would not work after replacing the light bulb. We checked the fuse for the headlights and they had not blown.

We had this problem on an Oldsmobile but this issue may affect other makes and models.

Problem

• The low beam on one side not working

Cause

• Damaged wire harness inside the headlight assembly

Solution

One possible solution is to replace the complete headlight. Replacing the headlight can be expensive.

In this case, we decided to replace just the damaged wires and the connector. Since the bulb was a 9006 type, we purchased a connector for 9006 light bulbs online.

Here is how we fixed it:

1. Turn off the headlights and open the hood.

    

2. Remove the headlight. In this case, removing the headlight was really simple.Remove two tabs and the headlight pops out. In some cars, you have to remove the front bumper to remove the headlight. If that is the case, check if you can access the damaged wires without removing the headlight.
3. Remove the cover from the back of the headlight assembly.

    

4. Remove the old bulb and cut the damaged wires. Keep the wires as long as possible.Don't keep the wire if the insulation is exposed. Unless you plan on insulating the wire.
5. Connect the new light bulb connector. Match the wires. Red is positive. Black or white is ground. In some cars is positive. This is important especially if you have installed LED bulbs as they will not work on reversed polarity.
6. Install the new light bulb, connect it. Lastly, install the headlight assembly.
7. Turn on the lights and make sure the headlight is working.

Conclusion

If your headlight doesn't work after replacing the light bulb and checking the fuses, make sure to inspect the wires inside the headlight.