Headlights Turning on and off

sounds like a short somewhere along the line...maybe a fuse that is ready to completely fail...

 

I doubt it. Do you actually have HIDs?

In this order, it's likely the bulbs, ballast then wiring. Start w/the bulbs. See Headlights...WHY so expensive...any alternatives?!?!?! | PriusChat.

 

I do not personally have HIDs...does it matter? I was just throwing out a couple ideas...maybe something failing along the way. I was thinking a fuse would be something quick to check/try. As you mentioned with wiring...maybe something is frayed somewhere. Again...just spitballing. I'll certainly defer to others with more expertise on the subject.

 

It does. I do and I've personally experienced them being intermittent and had to replace one of mine. Even the class action notice found at Toyota Prius Class Action Lawsuit | Toyota Headlight Lawsuit | Girard Gibbs LLP discusses the symptoms of them being intermittent.

I replaced one of mine around the time of can't remove washer fluid tank, trying to replace passenger side HID | PriusChat and bought my 06 new in January 06. Since the OP has an 07, it's not surprising that his HIDs are going out now.

Please also read Not all HID Bulbs are created equal | PriusChat about failures. Also see http://priuschat.com/attachments/hid-bulbs-pdf.20792/ (prior to the settlement).

 

This is usually the sign of the HID's reaching the end of their service life. Replacing them both as a set is a good bet and Priuschatters have had great luck with the Phillips (OEM) bulbs, which can be bought on Amazon for a song and dance (compared to what the dealers charge!!) of around $45/each.

 

Hopefully you ordered genuine Philips D4R bulbs from reputable resellers (e.g. Amazon and not a 3rd party reseller there).

As for your 04, it's not surprising. It seems the D2R system used in the 04-05 is a lot more reliable. See 04-05 (NOT 06-09) Prius owners w/HIDs - how long did they last? | PriusChat.