High Beam Drls

[wwest]

I first noticed this on my '01 AWD RX300, at fairly low miles the glass encapsulation for the high beam bulbs was internally "sooted" over and there was a bubble in the glass above the filament. I had upgraded to PIAA higher wattage bulbs so I guess I wrote it off to that, PIAAs, although I had found documents on the internet in operating halogen bulbs as DRLs at low voltage could result in those effects.

Yesterday I had to replace a burned out low beam in our 95 LS400 (210,000 miles). In the process of replacing the high/low beam H4 bulb I noticed that the second high beam bulb (60W HB3/9005), the one used for DRL, looked odd, bluish. When I removed it it was as I described above for the RX300.

So those of you with high beams as DRLs might want to check the condition of the bulb.

[SW03ES]

I just noticed the exact same thing on my car, and in fact I replaced both the high beam bulbs even though they weren't burnt out.

I'd hate to have one of them burst and ruin a $1000 headlamp assembly...

[wwest]

The bulb on the left was removed from my 2001 AWD RX300 about 5 years ago, probably at about 12,000 miles. I gave the other one to the service manager at Bellevue Lexus. The two on the right were removed from our canadian origin '95 LS400, 210,000 miles, just last week.

Halogen bulbs apparently do not fare well when operated as DRLs at seriously sub-standard operating voltages.

[SKperformance]

Odd , i have never seen this before. All my cars have drl's and it just browns the glass but never a bubble.