2011 Prius blows headlamps way too often, not HID

No ideas, but I can empathize. Last week both of my headlights went out at the same time. I've had the car for exactly 2 years and 20k miles and so far I've replaced both bulbs twice. Not necessarily a huge problem, but the Prius is already competing with the total number of headlight bulbs I've had to change in 25 years. I searched this site to see if it might be a common problem, and it looks like maybe just a few people have similar complaints. Just make sure to document everything. At least you'll know what you're talking about if you have to make that complaint to the dealer.

 

Could be vibration and cheap bulbs. In reality most of the bulbs are made in China, probably by the same people. Try the autozone bulbs.

 

Are you the original owner, if not was there ever a fender bender that damaged the wiring harness?
Lots of gen2's had hid problems, this is the first gen3 headlight problem to surface.
Err, mice?

 

It's difficult for me to understand how wiring would blow out bulbs. If anything, bad wiring might add resistance to the circuit which is only 12v and reduce amps dimming the bulbs. Arcing at the bulb contacts might be a problem but that would be clearly evident, both in operation (flickering) and at replacement (blackened areas). Even vibration is questionable for these kinds of bulbs. I would wear disposable nitrate gloves when changing them and ensure there is no moisture in the housing.

 

I think there was a TSB on defective headlight wiring in Prius, which causes bulbs to burn often. It was mentioned here at Priuschat. Your dealer is probably unaware of this TSB. Look for a better dealer?
In any case the bulbs would burn out fast when there is either too high or too low voltage on them. For a proper long life of halogen-filled bulb the temperature inside should be high enough to allow for halogen cycle to restore the filament material. Low voltage would cause temperatire to be low. The voltage too high is unlikely in Prius as there is no alternator+regulator. 12V is made inside inventor and is well-controlled by electronics. Defective wiring or relay can cause voltage at bulb to be too low. Another thing to look at is a plug that connects into the bulb.... if it has bad contact it would overheat and melt, but that is probably not your case.

- Alex

 

The instant the bulb is turned on is usually the time they burn. At this moment the resistance of the metal filament is the lowest that causes the highest current. As filament heats up, the resistance increases and current decreases

- Alex

 

You could check the voltage from inside the car with a lighter plug hooked up to a voltmeter and watch the voltage as someone else drives with the headlights on (they are a high load). It will probably start out at 14.8 vdc and go down to 13.5 vdc. You would need voltage pretty high (let's say 18vdc or more to blow out the bulbs), which I serious believe would cause damage to other bulbs and parts. You can also watch voltage on the MFD but it may not be as realtime. The voltage anywhere in the car will read the same in an overvoltage condition. Also watch for flickering or changing intensity of the headlights at night.

 

The problem is most likely the voltage AT THE BULB, not at the cigarette lighter. They will always will be different as The wiring path is different for those two.

- Alex

 

I have the same problem with my wife's 2011, it blows.....

 

Are you leaving the headlight switch turned on when you park, letting them go off and on automatically?

 

Are you leaving the headlight switch turned on when you park, letting them go off and on automatically?

My wife does, she likes that feature, tho

 

The OP lists no location in his or her profile. If he or she lives and drives the car in a seal coastal area or one where they heavily salt the roads in the winter, I'd suspect corroded or loose connections.

Also, a cracked housing or bad seal in the headlight housing may allow water vapor to intrude, corrode the connections or even affect the surface of the bulb.

 

In the last 10 years that I owned Prii, I never had a corroded lamp contact; maybe tarnished.......

 

One, two or even three units do NOT count as a "representative sample" in statistics.

As for the OP, I would connect an ohmmeter through the fuse block to check the headlamp circuit for a "phantom" drain or a short.

 

There have been numerous other threads on this topic. Some members have theorized that leaving headlights on like that subjects them to damaging voltage spikes. I'm not sure whether that's true, but why take the chance?

 

I had a 2011 Prius Two for three years. I put 48,000 miles on it and never replaced a headlight bulb.