Changing RX400h low-beam headlight bulbs...

[TomRX]

Now the time has come to do the low-beam xenon bulb job. 
I fixed the exhaust pipe between the cat and middle muffler and removed the weight and heat shield on the process. Nothing to do with the headlamp low-beam bulbs but I’m just so confident after the success in exhaust repair that I’m ready to do the low-beam job too 😄

Only thing that I’m not sure about is the electric high voltage warning signs in the engine bay. Is there a risk of getting a high voltage electric shock when replacing the xenon bulbs?

As a precaution the battery needs to be disconnected?

What about the ballasts? And how do I know it’s the bulb that’s bad and not the ballast?

The left side low-beam went off completely a few months ago and the right one is very weak in lighting power. 
 

I will start by removing the bolts from headlight assembly and take the bulbs as a reference when buying new bulbs. I guess I’ll go with the mid-priced bulbs. Meaning that they cost about $50-60 each. 
I can get them from local automotive parts store.

 

 

[Chief Boats]

Great thread, lots of good gouge. I noticed this morning that my passenger side low beam bulb is out and am thinking about replacing it myself (although I'm questioning that after watching some videos and reading this thread lol). I have a 2008 RX400h. My question is can you tell which bulb you need (DS2 discharge or halogen) WITHOUT accessing the light housing? the owners manual gives both as possible replacement bulbs on page 449 (but lists only the halogen on the diagram pg 373). I don't want to go through the process of disassembly and re-assembly just to find out which bulb I need then do it all again after I get it. OR are they interchangeable? I got the impression that each type as a different style plug. I'm the third owner and do not know if/when the bulbs were last replaced but none have burned out on me until now.

[Randy25]

My Driver's side Low Beam is pretty much out. In certain situations it still turns on, but only when I'm shifting gears. On the open road it's dead. I brought it to a mechanic at Pep Boys, who has two RX400Hs himself, and he told me to order the Headlamp Assembly on eBay to save many hundreds of $s and he would install it in 2 hours (removing the bumper). So I ordered one, brought it to him and he noted "The ballast is missing and this is manual focus, not auto-focus! Return it and order one that is Auto focus."  . . . . So I went back to the eBay vendor and he is now trying to get out of accepting the return. He's giving me some BS that he can provide me a partial refund if I hold onto the product (which I'm not going to do). But I've messaged a few other vendors through eBay and have yet to find an Autofocus assembly. Where can I find one?? I have a request out to LexusPartsNow as well. Waiting for someone there to get back to me.   

[ChrisColt]

To answer your question regarding how to tell if your RX400h has just halogen (low & high beams) headlights or HID (low beams) & Halogen (High Beams). The answer is in my description of the 2 possible factory headlight configuration options with the HID being extremely more expensive when new as an option. If the high and low beams (pick a side drivers or passenger and look closely at the headlight) There is a left and right-side bulb assembly housed in one overall assembly. I have the HID low Beam option and my headlight assembly has 4 bulbs per side (driver & passenger) - a Daytime running light & amber turn signal (low wattage, I think 3 watts halogen mounted higher up in the fixture for the white daytime bulb) and on the outside edges for the amber turn signal bulbs. Then there are 2 main bulbs centered in the left & right-side compartments of each fixture - if the two bulbs look identical - then you have the standard dual Halogen set-up. If one of the bulbs has a "fisheye" Lens over the bulb - looks like a sub=assembly inside the overall fixture housing - it is a round fisheye lens cover that is approximately 3 inches in diameter - whereas the high beams in both options are standard bright Halogen Bulbs with no additional lens cover inside the main fixture housing. To verify which bulbs are the high beams - turn on car/headlights (switch to manual ON instead of "auto" on the headlight control stick on steering wheel if it is daytime - otherwise your low wattage running lights will come on rather than your low beam headlights - note which bulbs are lit inside headlight fixture - these are your low beams - then flip your headlight stick to high beams on - now you will see your halogen high beams on along with your low beams - the HID low beams look completely different than your halogen high beams - if you can't see any difference between the two then it is safe to bet you have the standard halogen high/low beam headlight package. Another surefire way to tell is have someone sit in driver's seat with ignition off, keys out. Then with you standing in front of car have the other person start the car while you are watching one of the headlight assemblies and turn on regular low beam headlights - if they are HID you will see the headlight move up and down quickly as soon as they are turned on = this is the auto-leveling system/motor running its self-check start-up procedure = it looks like the headlights are nodding up and down for a second or two before stabilizing in the center. The Lexus self-leveling HID headlight system automatically levels headlights while driving to adjust vertically as car load changes (rear passenger and cargo weight changes) and left to right - horizontally - as you are driving around major road curves = the sharper the turn, the hillier the road surface and the more weight that may shift in rear passenger and cargo area, the more the headlights automatically move to track the road and attempt to stay perfectly centered on their "X and "Y" Horizontal & Vertical axes. So, the huge expense of the HID headlights in a Lexus is not just the cost of the bulbs and high voltage ballast needed for HID Xenon lamps, but also the processor/gimbal sensors/motors needed to move these HID sub-assemblies in 4 directions.

The Outer main lamps (not the turn signal lamps on outer edges) are the low beams while the inner main centered lamps are the for the High Beams. You can Google or Ebay Pictures of the Standard 4 bulb all Halogens vs the HID/Halogen upgrade. For NEW Standard Halogen complete fixture assemblies Lexus RX (Hybris and regular gas RXs) 2004-2009 (driver & passenger side assemblies) are selling for around $300 - $400 with bulbs included. For USED/Refurbished Xenon HID/Halogen for 2004-2009 Lexus RX (hybrids & regular gas RXs) between $300 to $900 EACH/per side or $600-$1,800 for a pair - with bulbs and ballasts - price differences are typically related to condition, appearance, warranty, complete or small parts missing etc...

Replacing burnt out HID bulbs used to be a very expensive proposition but the price of these bulbs have come down dramatically over the years as many are now made in China whereas back in 2004 - 2010 they were made in Germany and patented. Mine are 15 years old original set, some are saying the new replacements @$15-30 a pair last only 2-5 years (life rating 3,000-5,000 hours) very limited warranty, can still buy German brand at $30-$50 each. The shift is LED replacement for these HID high voltage (hence the ballasts needed) bulbs- they run $49 - $100 a pair with a 30,000 hour life / 2 year warranty, higher lumen output (brighter/less power consumption) and a choice of color rendition (from stock - HID equivalent of 4,300K to as high as I found 8,000K) the higher the Kelvin (K) rating = the more blue the white light will look, the lower the Kelvin rating - the more yellow/red the lamp looks - daylight is considered 5000-6000K warm white is 2500-4000K, cool white is 6500 - 7500K.