My son's friend has a 2005 Highlander that I've been helping him learn to maintain. We had a huge rainstorm on Monday, and when he pulled in yesterday to do an oil change, his driver's side low-beam was out and the headlight had about 3" of water in it. After changing the oil, we removed the headlight, drained it, and sealed it with silicone sealant. The water was high enough in the headlight that the connectors for the bulbs (high beam, low beam, turn signal) were wet inside. The driver's side low beam was blown (the glass was no longer present on the headlight bulb), so I replaced it with a known good bulb. Still didn't work. So I checked the fuse for the driver's side low beam, and it visually looked OK, and had continuity - 000 ohms on the meter. I'm kicking myself for not switching that fuse with the passenger side low beam fuse, so that's the first thing I need to check. I checked for power at the low beam headlight fuses with the low beams on, and got 12.xx volts at the passenger side fuse, but nothing at the driver's side low beam fuse. So even if the fuse was bad, the problem must be upstream.
Has anyone run into this issue before, and what would your next steps be? Let stuff dry out and try again? If a headlight relay had failed/was failing, would one 3/4 headlights still work (both high beams and one low beam)? I'm trying to take reasonable troubleshooting steps to see if I can help my son's friend out, so any advice is appreciated! Thanks!
