Forums

Same with 2013. I just took it apart and lubed moving parts. Will report results.

CoPilot: You're definitely on the right track, and I feel your frustration — the 2006 GS300 HID system can be a bit finicky. If your high beams work but the low beams don’t, even after replacing the bulb, ballast, and assembly, here’s a focused checklist to help you troubleshoot: 🔍 1. Double-check the bulb type and orientation The GS300 uses D4S HID bulbs for low beams. Make sure the bulb is seated correctly and the connector is fully engaged — even a slight misalignment can prevent ignition. 🔌 2. Inspect the headlight harness Yes, testing the wiring harness is a smart next step. Look for: Bent or corroded pins Loose connectors Damaged wires near the ballast plug or inside the headlight housing ⚡ 3. Test for voltage at the low beam connector With the lights on, use a multimeter to check if power is reaching the low beam connector. If there’s no voltage, the issue may be upstream — possibly a relay, headlight control module, or ground fault. 🧠 4. Check the headlight control ECU The GS300 has a headlight leveling ECU that can sometimes glitch or fail to send power to the low beams. If you’ve swapped everything else, this could be the culprit. 🔧 5. Try swapping sides If you haven’t already, try swapping the working high/low beam components from the other side (bulb, ballast, etc.) to isolate whether the issue is with the parts or the wiring. You're definitely on the right track, and I feel your frustration — the 2006 GS300 HID system can be a bit finicky. If your high beams work but the low beams don’t, even after replacing the bulb, ballast, and assembly, here’s a focused checklist to help you troubleshoot: 🔍 1. Double-check the bulb type and orientation The GS300 uses D4S HID bulbs for low beams. Make sure the bulb is seated correctly and the connector is fully engaged — even a slight misalignment can prevent ignition. 🔌 2. Inspect the headlight harness Yes, testing the wiring harness is a smart next step. Look for: Bent or corroded pins Loose connectors Damaged wires near the ballast plug or inside the headlight housing ⚡ 3. Test for voltage at the low beam connector With the lights on, use a multimeter to check if power is reaching the low beam connector. If there’s no voltage, the issue may be upstream — possibly a relay, headlight control module, or ground fault. 🧠 4. Check the headlight control ECU The GS300 has a headlight leveling ECU that can sometimes glitch or fail to send power to the low beams. If you’ve swapped everything else, this could be the culprit. 🔧 5. Try swapping sides If you haven’t already, try swapping the working high/low beam components from the other side (bulb, ballast, etc.) to isolate whether the issue is with the parts or the wiring. This video guide walks through the HID bulb replacement and testing process on a GS — it might help you spot something you missed.

I suggest going to an auto parts store if they offer free scanning. If there is a code, that should reveal the issue. Maintenance required may indicate that an oil change is due. I noticed with my 2024 Supra that if I set the gas pump's trigger hold lever to max fill rate, it will click off before the tank is full. The last time I filled the tank, I set the fill rate to a lower setting. That allowed the tank to be filled.

Thank you Dave for your very extensive explanation. I am somewhat pleased to learn that there are solutions to the problem, but it sounds like it could be costly. The dealer that sold us the vehicle was not very forthcoming and made it sound like its not a big deal to change Km to MPH, and that it's something that can be done easily. We probably would have opted for a US version had we known this. I very much appreciate your very detailed information and hope we can resolve this somehow. It's a bit of a disappointment to learn all this after the fact.

I’m having a similar issue where the engine is surging then shuts off when warm. Did you ever find a solution?