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Curious if anyone had ideas on what could cause this. I recently bought an 08 LE in which everything works except the high beams.

When I pull back or push forward on the headlight control, I see the blue high beam light appear on the instrument panel but the actual bulb doesn't turn on. The low beams and turn signals work fine. I don't have DRL lights as best I can tell. There's no "auto" DRL toggle on the headlight control & the #2,#3,#4 DRL relays in the under hood fuse box are empty (hope that normal?)

No luck after replacing the bulbs and the fuses look ok. I heard the emergency parking brake might affect this, but when I push it on/off, it didn't turn the high beams on.

I've tackled some DIY repair (exhaust, radiator) before but haven't troubleshot anything electrical before. Some tips would be greatly appreciated!
 

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Looks that high beam doesn't work without DRL relays (at least No. 2, 3 and 4). See the wiring diagram in the file attached. It is from 2005 Sienna Repair manual (the download link is in my signature).
 

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Interesting, thanks for the diagram. I'll hunt down those parts and give it a try. I take it one should never see those DRL relays missing then on any model, DRL enabled or not.

Maybe this model had DRL enabled at one point and the last owner wanted to disable it? I'll reach out to them too and see if they know anything about it. Being a private sale, they may not want to say too much though.
 

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How about the simple explanations for high beam bulbs which don't come on, in any mode (DRL or not):
  • Are the bulbs burned out?
    • they are completely separate from the low beams, and the low beams stay on when the high beams are turned on, so someone driving only in city could go for a long time and not notice
  • Are the high beam fuses blown?
    • there is a separate fuse for each, used for nothing else so someone not using high beams would not notice
I'm not saying that it is one of these, but it makes sense to me to check the most obvious causes - and easiest to check - first.
 

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I did check those two items (with a new high beam bulb & fuse) but no luck unfortunately. I ordered the missing DRL relays from RockAuto.com & will report back my results soon.
 

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The DRL system on the 2008 model works differently than it does on the 2005, so the wiring diagram in the 2005 repair manual does not apply to you. However, you still may have a missing or bad relay that is causing the problem. Relay failures seem to be rather common.
 

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Discussion Starter #7
Update: I plugged the 3 replacement relays into the empty DRL slots and now the high beams work. Thanks everyone for the assistance!
 

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So these 3 relays were missing? Did the previous owner have any comment? Who would willingly strip out their high beams?
 

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That's right, those are the 3 that were missing which are highlighted in red on the right there.

I didn't get the story from the previous owner. Maybe they only drove around a city and never knew the high beams were out? It's a little odd, but I guess it could happen. I'm so happy this was a cheap fix, not much left in my pockets after leaving the DMV to get this one on the road!
 

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Glad to hear it had a happy ending, and credit to you for figuring it out. Something like $50 each though. Ouch.
 

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Old thread, but it sort of helped me diagnose my problem.

A couple of evenings ago, both my high beams went out at the same time. I figured it must be some fuse or relay, but looking in the fuse box, there's no obvious fuse for the high beams. I found this thread which pointed me toward the relays for the DRLs. I did some swapping still without luck. No high beams no matter what I did.

Then I checked the bulbs. Both bulbs popped at the same time. I replaced them both and my lights work again.

I thought for sure it would be the relays. But sometimes both high beam bulbs go at the same time.

Jamie
 

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Just a warning... The only time in my life that I lost two headlight bulbs at the same time was when an alternator needed to be replaced. The internal voltage regulator was spiking. In a way, the dead headlights served as an excellent 'heads up' that a problem was brewing before it manifested itself as an overvoltage damaged electronics module or something else expensive.

High beam bulbs can become very vulnerable over time. Their use as DRL at half voltage interferes with the halogen cycle that is supposed to redeposit tungsten back on the filament and maintain it's integrity. Instead that tungsten deposits on the inside of the glass making it dark, and it leaves the filament with thin spots. Those thin spots are then susceptible to damage if the voltage rises higher than it should, and both bulbs blow at once.
 
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Just a warning... The only time in my life that I lost two headlight bulbs at the same time was when an alternator needed to be replaced. The internal voltage regulator was spiking. In a way, the dead headlights served as an excellent 'heads up' that a problem was brewing before it manifested itself as an overvoltage damaged electronics module or something else expensive.

High beam bulbs can become very vulnerable over time. Their use as DRL at half voltage interferes with the halogen cycle that is supposed to redeposit tungsten back on the filament and maintain it's integrity. Instead that tungsten deposits on the inside of the glass making it dark, and it leaves the filament with thin spots. Those thin spots are then susceptible to damage if the voltage rises higher than it should, and both bulbs blow at once.
Thanks for that heads-up. My 05 with DRL just had both high beams blow - and I think one of the microfuses. I swapped all relays with my 04 (one at a time) and confirmed they were OK, but then found the bulbs blown. If this new set goes soon, I'll know to take a look at the alternator.
 
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