So the other day, my stepfather was following me in my car to their house and when we get there, he says I've got a brake light out (left). No worries, I think, and I don't even look at it. I just pick up a pack of bulbs on the way home and when I get home, I go to replace the bulb.

Only it doesn't look bad - looks fine. I still don't have a left brake light. Hm... So I check the other two bulbs just for grins, and they work. Then I turn on my headlights and look, and lo and behold the brake lamp (which does dual duty as the stop light and "nighttime running light" - I suppose that's what it's called; I never thought about it - is shining just fine. It just isn't activating when I push the pedal. What's supposed to happen if the headlights are on, is that the bulb should be on, but if you press the brake, the light should get brighter. If the headlights are off, if should stay off until you press the pedal.

Right side is working fine. I also noticed when I got to actually looking that the high mount stop light is apparently either burned out or also not working (I haven't looked at it's bulb yet).


So I looked in my Haynes manual for a wiring diagram, but I didn't see one for the 4runner exterior lighting system. Can anyone clue me in on what could be causing this problem?

 

the bulb is a dual filament bulb I believe-it is a marker light when your headlights are on and it is a brake light when you hit the brakes. One of your two filaments is broken or bad-you can't always see it, usually but not always-same with fuses.

Swap in your good right one for the bad left one and confirm diagnosis.

 

I remember a few times where I have bought the correct bulb but... bought a single filament, not the dual....opps....

but ya just swap the other working one, see if it works, if it doesn't...well then you have some issues.

My stupid brake light doesn't work for some reason either.....ummmm I wonder why????....... wierd.....

http://s201.photobucket.com/albums/a...t=Vegas406.jpg

 

Yup - that was it. One filament was broken, but it was hard to see. I got it working now. Thanks for the advice, y'all. These forums are great.

 

thanks for confirm on the diagnosis. glad we could all help you out.