I have a 1990 4Runner. A while back my headlights started burning out way too often. I have had to replace the last few sets of headlights (sealed beams) every few months. One will burn out after a few months and then shortly thereafter the other will burn out. The high beams still work but I can't drive around with them all the time. The one time that I noticed when a bulb burned out it happened just moments after starting the vehicle (don't know if that means anything). Does anyone have any knowledge/suggestions on this problem. Thank you.

 

have you tested the voltage at the light plugs?

too low, or even too high if you're vehicle's overcharging, can cause premature failure

what brand head lights are you using too?

 

Where are you located? Cold weather tends to zap bulbs.

 

Any moisture in the headlamp? A rock chipped a hole in mine once and as as soon as it got moisture in there it steamed up and blew the bulb. Had to replace the whole lamp (not cheap)

 

I haven't checked the voltage. If it is off what sorts of things would cause that? have used a couple of different brands of lights - sylvania, ge

 

Not cold here - west coast

 

well a faulty voltage regulator in the alternator could cause unusually high voltages, but you'de notice other problems too, like say, the battey boiling over, and the battery and brake like coming on in the dash

low voltages can be caused by bad wiring or bad ground connections


the bulbs are designed to operate at 12v, and usually a little more than that considering the average vehicle put's out around 14v while running

with the vehicle running and the head lights on (and plugged in mind you; as in the lights are lit up), you should probablt see 12.5-13 volts are the plug. I would go as far as to say that between 12v and 13.5 would be normal



yeah the Sulvania's should be good; I was just making sure you weren't replacing them repeatedly with some weird off-brand cheap-o light

 

Interesting I would have to say it is a voltage problem to much or to little.

I drive with my headlights on all the time and only have the odd burnt out light once in a great while.

** One thing I do with all my Toyota vehicles is upgrade the ground cables one to the body and one to the engine block with number 1 welding cable. I know it helps with starting and charging issues.

 

that will shorten the bulb life too

 

Bad Ground.

 

I had this problem after my last RC trip. Turned out it was a combo of a few things, I had moisture/mud in the headlight sockets which in turn led to a bad voltage regulator in the alternator.

 

studies do show it's safer though

apparently, even during the day, you've more visable with the headlights on. or at least other motorist see you sooner

that's why it's common practice now for the car manufacturers to put auto-lights on the vehicles that turn on when you put it in gear, regardless of the light outside

 

switch to an H4 housing with HIDs....

 

good idea as far as bulb life and visibility, but what about the ballasts that don't like severe changes in voltage.

 

I have measured the voltage as follows...

When vehicle not running:
Across Battery - 12.5v (13.17 volts shortly after turning vehicle off)

When vehicle running:
Across Battery - 14.47v
At Headlight - 14.06v

Are these readings a problem?

 

If I have reduced bulb life I have yet to notice.

What changed or what happened just before this started ??

Do you have any problems with any of the other bulbs besides the headlights??

Do you blow any of the headlight fuses ??

A loose connection that could cause a voltage spike perhaps??

While on the high end if your Meter is close it should not cause the problem.

I will do some checking