Headlight Allignment

Do you have the HID lights?

The lights have a height adjustment screw on each side. Sounds like you should aim them up so you don't have to use high beams all the time.

 

If you have a warning light on the dash about the headlight aim, you absolutely have the HID headlights. There is a sensor on the rear axle that tells the computer how to adjust the HID headlights

If that sensor is corroded, broken, or otherwise buggered up, the headlights will either be too low or too high

 

I think it more likely that the lights are plain out of adjustment, rather than a sensor problem. There is a height adjustment under the hood.

 

There was an issue with the 2004 & 2005 models and the sensor. The sensor is located on the left rear control arm and compensates the headlights for how much the rear end is sags with loads. It would accumulate road grime, corrode and stop working. When it did stop working it would always fail with the lights aimed as low as possible. It was worse in the cold, sloppy climates where they use a lot of salt. The senor was redesigned in 2005 to provide better protection against the elements. I don't know if this is your problem but it might be worth looking into. Seems to me there might have been a TSB associated with it.

 

I'm on the road, 600 miles from home, and Amapola, our '08
Touring, will be in the shop tomorrow for a 20K mi. oil change and
tire rotation. Additionally, I'm having the "tranny" oil changed --
because of what I've read on PC, not because it's required just yet.

More to the subject of this thread, it seems to me that the
headlights, HIDs, are aimed just a tad low -- only very rarely is
there a third person carried or appreciable weight in the hatch area.
So, I'm going to ask that they be be checked for alignment and even
if they're within spec, raised a wee bit.

I have no idea what the service writer/tech is going to say. But I
want to be prepared to be able to open the hood, and point to the
right places and say something like, "It's not the computer, and its
not the sensor on the rear axle, there's an adjustment right HERE
and HERE. Please take a minute and check it out in your technical
manuals. It should only take a moment or two to do."

So, can anybody provide a picture/drawing or cite to one so I can
get smart in a hurry?

Thanks in advance.

 

Search is your friend. The TSB is listed on post #3 of this thread:
http://priuschat.com/forums/prius-main-forum/23665-auto-leveling-headlights-cool.html

Tom

 

TSB = Technical Service Bulletin. I don't think Toyota USA make them available for free, but AllDataDIY.com has at least a list of titles (2005 Prius). EL004-06 might be relevant.

 

Another thing to keep in mind with the HID lights: a mechanical shutter is used to switch between low and high. It's not like a single bulb halogen where a different filament is used

 

Ever since I've had my Prius (brand new 2005), I've had oncoming traffic flashes that immediately stop when I give them my highbeams. I know they think that my highbeams are on until I do that.

I just called the dealer and asked if it's something that I can adjust myself or if it's something they need to look at. The service guy immediately said I need to bring it in to have it looked at. I then asked if it was a sensor issue and he said yes (in other words, there's nothing I can do about it on my own.) :-/

I asked if it would be covered under the warranty and then he asked how many miles I've got on it ... darn it. I told him almost 75K and then he gave me an "Oooooh. 3 - 36!"

So, the warranty on the sensor is only up to 36K miles.
That sucks.
I hope it's not expensive. I didn't ask. I was too frustrated at the thought of it not being under the warranty when I paid for the 75K one.

 

You can manually aim the headlights lower with the adjustment screws on each headlight. All you need is a philips screwdriver.

 

This is the location of one of the adjusting stars



A long skinny philips screwdriver can be inserted from above to engage the teeth on the adjusting star. Or, put a socket on the end and use a 1/4 drive ratchet.

It helps if you back into a garage, then close the garage door. Turn the headlights on, they have a sharp cutoff on low beam. Use masking tape to mark the cutoff.

Then, adjust both headlights about an inch lower. See if that helps. On low beam, I try to adjust them for 30-50 ft ahead of the vehicle. This is trial and error, it will take a few tries

When my Prius was new, the low beams lit up the tops of trees!