How to Replace HID Headlight Lamp at 200k

I'm certain that this forum contains ample rants about Toyota's terrible HID headlight design. Most are about the short life of the OEM bulb and ballasts. Less has been written about the difficulty of replacing the HID bulb itself at 200k on the odometer.

While I nurse my cuts and bruises from this job, I'd like to share my experience with you dear PriusChat readers.

This is the second time I've replaced my HID lamps. The experience this time around was far worse than the first one at 50k miles.

There is a domed plastic cover over the rear of the HID bulb and its tilting mechanism. (Toyota uses an electric solenoid to tilt the lamp for high beam use.) The domed cover has twist 'n' lock retention with a rubber ring gasket embedded in it.

When the car was young the gasket was pliable and you could still remove the domed cover with your fingers. By 200k miles the rubber gasket bond has bonded itself to the mating surface and the cover won't twist with finger pressure.

I used a giant pair of Channelock pliers and tried to twist the cover off, but its tabs snapped off. There isn't enough room behind the headlight assembly when it's installed on the car to grab the cover itself without the twist tabs.

At that point I resorted to removing the entire headlight assembly from the vehicle. It's secured with three bolts with 10mm hex heads. Two of these bolts are easily accessed from the engine compartment, but the third is under the bumper cover.

YouTube videos show how to remove the entire bumper cover, but I got by by only loosening the end of the bumper cover when it terminates at the wheel well. Removing the one fastening bolt at the end of the bumper cover allows you to yank on the cover to free it from its snap-in bracket. At that point you can reach under the bumper cover with a small 1/4" socket wrench and free up the third headlight bolt.

However, you need to watch the YouTube videos to know where this 3rd bolt is located.

When I finally got the headlight off the vehicle it became clear that the torque required to twist off the domed cover is far greater at 200k miles than it was at 50k miles, and far greater than one can muster with fingers alone. The torque is not even close to what Toyota assumed it would be

It took the big nice person Channelocks and enclosing the headlight assembly with my thighs and knees to wrench the domed cover off.

Although I suspect that someone else will own this Prius when these bulbs need replacing again, I cut the poor sucker some slack and lathered silicone grease on the gasket before I reinstalled the domed covers.

Jim Olson
Indianapolis, IN US