2007 Prius HID headlight problems

dont know the answer. but i am in the same boat \.
ordered a set of hid bulbs, hoping that will solve the problem .

 

There are many threads re. HID bulbs, here on PriusChat, and the general consensus is avoid the cheapies made in China (usually found on eBay or the InterNet - and go with a reputable source (e.g. Philips or Sylvania) - hope this helps - Wil

 

I would suggest you use the "search" function - I think that's what I would do - good luck!

 

Well, I'm so sorry that my response didn't satisfy your need for an instant answer, but when I experienced exactly the same problem as you seem to be having, I was able to find an answer which solved my problem by using the "search" feature… …and doing lots of reading! (…damn! sorry, I'm repeating myself, so I'll shut up!) Good luck!

 

Feel free to call me.
It'll cut down on the search a bit.
But basically it's a known issue with the Prius.

Several ways to tackle it.
None of them cheap.

 

My money is on the HID bulb. There's no guarantee, but between the age of the car, the failure mode of HID bulbs matching exactly what you describe, and both bulbs doing it, but the problem not starting at the same time, I'd give it at least a 75% chance. My first HID bulb died with exactly your symptoms around 250,000 miles, the other one six months later.

The only way I know of to test this to be sure this is to try replacing the bulbs. If new bulbs also do it, then it must be the ballast. But it would surprise me.

The bulbs aren't cheap, but also not outrageously expensive - around $90 each; I bought mine at O'Reilly, but most auto parts stores have them. You can replace them yourself. How much longer do you plan to keep the car? That should also be a factor in deciding whether you get brand name bulbs, cheap ones, or simply replace the car now. Shortly after I replaced my bulbs, my Prius started developing a lot of age-related problems. The next big expense is likely going to be the cat, a $2000 repair in California (in other states, you may be able to use cheaper aftermarket cats). Also, your engine may wear out, as well as some other components.

One hint: for replacing the HID bulbs, follow the actual Toyota instructions that have you take off the bumper first to get to the headlight assembly to access the assembly from the front. There's a reason the engineers came up with those instructions.

You will find quite a few instructions on the Internet about an "easier" way to do it by taking out some components on the top and getting to the lights from behind. Don't. Do. It.

I tried both approaches.

These Internet-based instructions *seem* easier because they resemble how you change headlight bulbs on most cars, but you will be contorting your hands while trying to undo a cover that is very hard to take off. You may end up having to use a tool to take the cover off, and then break it in the process.

Taking off the bumper sounds more complicated than it is. It's actually only a few screws and takes maybe ten minutes tops, but it will allow you to take out the headlight assembly and work on it very comfortably; you can even disconnect the assembly completely and work on it on a workbench. And because you would be replacing both bulbs, you are saving yourself twice the contortion, and have to take off the bumper only once.

Another tip: my car guy warned me to be careful about *which* wires in the harness you disconnect, because the airbag sensor is in that same region. You may want to disconnect the 12V battery just to be safe, especially if you plan to take the assembly out and work on it elsewhere.

 

It's MUCH cheaper than it used to be - due to folks like the ones at Luscious garage - cutting the headlight change out time (thus, hourly expense) for a major function to under 3 minutes !!!

.

 

It's the bulb. If your ballest was bad it would stay bad. The xenon gas eventually dissipates and won't reliably ignite an arc. Turning them off and back on sends another high voltage pulse and usually gets them going. This trick works for about a month. Here's a thread on the topic. Headlights working intermittently | PriusChat

 

It is not likely to be the bulb.
At times it can be the ballast.
Or, there is a theory about it being a loose crimp connection that can be corrected with resoldering.

Most techs will take 20 to 30 minutes to change a light bulb. It involves dropping part of the bumper and extracting the headlight assembly. That is the most reliable way for most people to do it without getting cut up or damaging the surface of the bulb.

 

The important part from that post.
When you get the headlight out, this will make sense....

"... the problem is the red-black wire pair inside the headlight that provides twelve volts to the headlight power supply.

Over time, the crimps become high resistance and act like a thermal switch.

You can take the plugs apart and solder the crimps..."

 

error. please delete

 

Ballast06 by ericbecky posted Feb 25, 2016 at 3:23 PM

Here is a pic
(It is from a great tutorial about replacing ballasts)
http://priusdiy.com/images/lighting/ballast06.jpg

 

$184.80 each for 81107-30D31, here:
HEADLAMP COMPONENTS for 2007 Toyota Prius