Q: Both High Beam and Low Beam Not Working

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Both of my HID low beams and High beams are not working, all four bulbs. I basically parked my car and after few hours when I got back in my car and turned the headlights on, they never came on. I checked all the fuses and relays and they're in perfect condition like nothing has happened. There are two hidden relays under the steering wheel and I don't know what they are for and I can't check them because they're fully fixed into the multiplex control unit. Maybe they're the main relays?. I took out the high beam harness from the bulb and plugged my black wire of the multi meter on the negative battery terminal and the other wire on the bulb harness and there's ground on both the wires of the harness, not sure if that's right or not. all I can tell is that there's no power coming to the bulbs and when I turn the high beam on, the switch goes back to the off position and the high beam indicator never shows up. I replaced the switch but that didn't fix the problem.

My car has 166234 miles.
My car has an automatic transmission.

It’s possible that your headlight switch is the source of the problems you’re having; (especially if it’s all headlights that are not working correctly). It’s also possible that you may have an exposed wire somewhere creating a short in the system. The best thing we can recommend is have a professional mobile mechanic come to your location to complete a headlights is not working inspection; so they can pinpoint the source of your issues and recommend the right repairs.

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Hi there. This sounds like there could be a fault in the multiplex control unit, communication network, etc... The HID headlight system on newer vehicles is much more complex than those of many years ago. There are computers, inverters, high voltages, sensitive components (oil from your fingers on the HID bulbs will cause them to fail prematurely), shielded wires, etc... Always check the basics first, the bulbs. More often than not, we don’t realize we have a blown bulb because the light is so bright from these systems that we can’t tell if only one bulb is out while we’re driving. Then the other bulb goes out and we think they both went at the same time; it does happen. However, there could more to your situation and this calls for the proper tools and information to properly and safely diagnose the system. There are multiple grounds for this system; computer grounds, switch controlled ground, computer controlled grounds, inverter grounds, etc.. I suggest having a qualified technician perform an inspection to avoid replacing unnecessary parts. Your Mechanic has several available technicians that can assist you with a headlights are not working inspection.

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