Headlights Burn Out

Those have recently been electronic but still essentially acting on the same principle as the old vibrating reed, modulating the current to the alternator's stationary field coil, to influence the output from the rotating armature coils. The vibrating reed versions gave very coarse control, usually having about three levels of field current (too low, too high, and one in between, produced by a voltage divider when the reed was touching neither contact). The 'electronic' alternator regulators replace the reed with solid-state components, but there is still a difference between that kind of regulation and the Prius DC/DC converter, which benefits first of all from a more stable input voltage to begin with, and then is structured very much like the switch-mode regulated power supplies you find in all of today's computer and electronic equipment, only big.

I see the form of an argument by contradiction here, but there must be a problem with it somewhere, as conventional cars historically have had quite wide voltage swings with engine RPM, and yet did not pop headlamps all the time.

I might not be able to pin down what goes awry in the argument, but it does seem to have an unstated premise that voltage variation would be the worst thing for lamp life, and maybe that's the hitch. Maybe well-regulated—just constantly too high—voltage shortens life more.

-Chap

 

Maybe someone here knows some specifics for the Prius 12V converter -- oscillator, regulator and filter. I see that high voltage converter has been dissected, at least for Gen2. I agree that the consistent input voltage should make converter design less complex. But, I seriously doubt that large electrolytic filter capacitors are used at the output since these are typically the least reliable of any electronic component. The role of the cranking battery as a filter for an alternator system is well documented. And I would say that electronic alternator regulators provide "precise level control of a known, non-DC, waveform". In the automotive world, "vibrators" refers to the crude oscillators used in the B+ power supplies of tube-type radios.

I don't think we can guess as to the reason for certain Prius VINs popping headlamps. It could be the wiring harness, or some other system difference for which the revised harness compensates. It's nice that it's getting fixed.

I'll still log my DC voltage and report it beginning just before a cold start. Logger resolution is 50mv. This may not reveal much since my vehicle has good headlamp life and I won't see spikes. But it might be of general interest.

 

The circuit for Gen 2 is shown in the 2004 New Car Features Manual, page TH-33. The Gen 3 converter is probably shown in the corresponding section of the Gen 3 NCF, but I've used up my techinfo time for now, so I can't point to the page. The diagram in the NCF doesn't give component values though, and the "control circuit" is just shown as a function block.

Sometime PriusChat member hobbit has done what might be the most detailed teardown of a Gen 2 inverter, though most of his attention was on other modules of it.

For ripple, certainly. Yet at the same time, conventional engine/alternator/battery systems had visible-to-the-naked-eye voltage variation on macro time scales, corresponding to engine speed. These aren't mutually exclusive.

I'm not sure I've caught your train of thought here; I see I mentioned automotive vibrating reed voltage regulators upthread, but I don't see what unrelated other uses of the word 'vibrator' do for us where headlights are concerned.

All measurements are interesting, but again, I don't know that 'spikes' (or ripple, for that matter) will turn out to be an important factor in headlamp life. Incandescent lamps are pretty good averaging devices for short-scale variation—heck, people have even been known to run them on AC!

-Chap

 

>>>>>>>>>>>> if you happen to still have the car after all this time are you still having good service out of the HID's?
I am having the same problem and was leaning toward it being a "water/moisture" problem, until you said the HID's fixed your problem. Reason I say that, is it sure seemed to me like there was way too much moisture in that area when I pulled my last blown bulb, and we just went thru a lot of rainfall here.
Anyway please do let me know how those Hid's worked out long term? ---- Also let me know if you would consider LED's instead of HID's? THX soooooooo much! Any help will be greatly appreciated! XD

 

Update - a year after installing LED bulbs, they are still working fine, nothing has burned out or shorted out or anything. However, they are noticeably much dimmer than halogens. I don't drive much at night so it doesn't bother me, but if I did, I would be replacing them with HIDs.

The other, more pertinent update: Last week I received a notice from Toyota that they have initiated a Customer Support Program, which extends the warranty on my 2010 Prius, *regardless of mileage*, and they will now replace the low beam wiring harnesses and low beam halogen bulbs free of charge.

I'm definitely going to take them up on that.

 

wrydere,
Can you point to a link or provide more information about the Customer Support Program that you mentioned?
Thanks in advance.

 

@ericbecky - I can't seem to find it online. I'm attaching a scan of the notice that I received. There's also another thread started here about the program: Customer Support Prog ZHB Halogen bulbs | PriusChat

I took the car to the dealership this morning, they wanted to see receipts for the different bulbs I'd purchased over the years, which I don't have, I don't save small receipts like that. I think I have convinced them that I'm not trying to scam them for a free wiring harness and that I'm not exaggerating when I say that I've replaced the low beam bulbs close to 10 times in 7 years.

 

Thanks for the copy of the notice.
Very interesting.
Looks like a google search for "customer support program zhb" only turns up your post about this program.

 

I just received my letter for this new program. I assumed my long commute during winter nights killed my bulbs. I have replaced them both every year I have had the car. The passenger one always blows. I wonder if I can find all the receipts... doubt it.

 

I also just received my "Customer Support Program Notification - ZHB" letter yesterday.

Shortly after I purchased the Prius just over 4 years ago one of the headlights went out. I installed a set of Osram H11 Made in Germany bulbs & have had no problems since. After reading about the H11 to H9 bulb conversion I recently purchased a set of Philips H9 bulbs from Ebay. Turns out they are Made in China but oh well. I had modded the H9 bulb base & connector a few weeks back & was waiting to install them.

Yesterday evening I removed the air intake plumbing & two bolts holding the ICE coolant tank in place. It was _easy_ to get to the passenger bulb to disconnect the connector then remove/replace the bulb. I think moving the coolant tank a little really helped. Drivers side was a piece of cake. Took it out for a spin & I do have more light - yay!!

I have an upcoming road trip planned - that was the real driving force to get these installed

 

Since I purchased my Gen3 Prius 2010 in July 2015, I replaced the f!@#ing H11 bulbs like 30 times. This is not related to quality and price of the bulbs nor wearing gloves or using other Jedi tricks mounting the bulbs. The problem is not related to my Taxi equipment and LPG installation, because the problem existed before. Since I put on LPG, my LPG computer burned now twice along with a bulb.

After chasing the Toyota dealer, where I bought this car as used, they just ignored my problem by only offering me to change the burned bulb. I am now with another Toyota Dealer, who took me seriously and made by themselves all the checks and test I requested the first dealership to do. My car has been diagnosed with an unusually higher voltage and we are now waiting for Toyota to respond to the report. I will show them some posts from this and other threads, but in my opinion LEDs or wire harness mod sounds good to me.

 

How many Volts?
But, since you modified the car, you are on your own.