We have a 2018 T4R and it seems like we are only getting 3-4 months out of our low beam headlight bulbs. We have tried OE bulbs, Phillips bulbs, and Sylvania and all see to have the same problem. There has to be something causing them to fail so often. Has anyone else had a similar issue, or know what might be causing the bulbs to fail so often?

Are you using the higher output bulbs? Those last far shorter than the standard output bulbs. Also skin oils on the bulbs causes them to fail early.

+1 for above. Should not touch bulbs with bare hands.

+2 on not touching bulbs with bare hands.

What is your battery voltage when the engine in running? If the voltage regulator has failed, a high voltage will burn out bulbs fast.

If you are getting oil on the bulbs from your fingers, you can clean them off with a clean tissue with some Isopropyl rubbing alcohol on it. I prefer the 91% formula.

I typically don't touch the bulbs with my fingers for that reason, I was thinking something with the battery. I will try to check the voltage while running to see what it is.

Usually this is a wiring issues. Bad ground on the plug, shorted wires, etc. This causes more heat, voltage and will wear out quickly.

I will look into possible ground issues later. In my experience a bad ground will cause a lot of other issues as well, which we haven't experienced.

I just checked voltage and am seeing 12.5V with the car off and 14V with it running.

For what it's worth. I am not sure if this applies to projector style lamps, but higher output lamps, such as Sylvania Silver Star and Silver Star Ultra in my experience burn out quickly.

In an '06 Honda CR-V I used to own, my low beams would last a month or less. After replacement under warranty a couple times each, I gave up and went back to OEM and never had an issue thereafter.

On the CR-V and many other cars with headlamp parabolas of that type, the bulb had a little "umbrella" (for lack of a better word) over the tip of the bulb. This umbrella actually reflected light from the end of the bulb back to the parabola for projection out. My thinking was that the bulb was overheating and burning out prematurely.

Projector lamps, such as those on our 4Runners (I also have an '18), I assume don't have any heat trapping features. However, I really don't know what they look like inside their housing, nor their design, as I've not changed them on my 4Runner or my '12 Subaru Outback (also with projector lamps).

Do you have an infrared thermometer? If you do, shoot the bulb, plug, surrounding areas and compare to the good side. See if the bad side is considerably hotter.

Also, test amperage of bad bulb compared to good. Test while blinkers are on, etc. See if some scenario is sending spikes to the bulb. Examine the plug for burned marks-take bulb out and look at connections.

It definitely seems like a wiring/ground issue. I would check the connector/wiring harness to make sure nothing is pinched or shorted. Check to make sure you have the right fuse for the headlights. I touch bulbs all the time (on accident of course) and never have bulbs pop like you seem to be going through.

14v? Do you have a voltage booster or is it cold? Seems high.

Still likely a ground issue vs a voltage issue.

2018 4runner @ 88k miles

Recently replace ALL bulbs, out of OCD.
The lover beams were dark and had one buldge on one side. Weird. Glad I looked them up.

All other bulbs looked ok, but replaced them anyway.

I am guessing the low beams were on their last leg.

I am thinking, it's a good practice to replace bulbs every 4-5 years or so, even if they don't go out.

That is normal.