My wife has the Prius. The lights have been terrible in it as long as I can remember. I don't know how many times I have ridden in it and gotten out sure a headlight was out, only to get in front of the car to see they weren't. It's honestly not safe to drive in the dark. My wife recently told me a headlight was out (at night) and I knew she shouldn't drive it, so I took it to go get a new headlight. I couldn't see to drive, so I switched to the fog lights(seemed they turned the headlights off?) because that was the only way I could see at all. Is there anything I can check? I swear the bulb shoots off in some incorrect direction or something. They are on, but I can't see the road. I can pull up to the garage door and they don't even light up against that. Thanks for any ideas.
One thought: in the early eighties, here in BC (Canada), you needed to run your car through a road-worthiness inspection, yearly. If it didn't pass, you were sidelined till all was remedied. They dropped that, converted it to emissions-checking. AFAIK that's gone now as well. How we progress. Ever any front end collisions? Are the %@&*! plastic frosted-up from UV exposure? Rodents?
Does the plastic lens need to be polished? Most tire & wheel centers will do it for $35. Check the bulbs are locked into the socket correctly. Push in + a quarter turn to lock-in Switch to 6000K LED bulbs with the big heat sinks. The ones without heat-sinks are worse than incandescent lamps.
Also forgot to mention that a bad/dirty ground connection to the car frame can cause that too.... You can use a DVM to determine if that's the problem. 1. turn on your headlamps 2. unplug your dim lamp. 3. measure voltage from frame ground to power wire 4. measure voltage from power wire to ground wire within the connectors. Readings should be the same as #3 - otherwise bad ground. hope this helps...