"Lamp out" warning, but no lamp out

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perpetualchange

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For several months now my lamp-out warning has come on regularly. I've tested all known lights several times and have no idea what is going on, since all are fine. I took it to autozone and they said the code was for one of the rear brake lights but both lights are obviously working.

If anyone could help me diagnosis and eventually repair that'd be great.
 
This comes up every so often on here. Every time, the claim is that all the bulbs are working, but every time eventually, it comes out that one of the filaments of one of the bulbs really is out. The brake lights are dual filament bulbs. Turn on the parking lights, and verify that all bulbs are lit, and that all are the same brightness. If one is dimmer or brighter than the rest, it's your problem. Also, be sure to check the tag lights. If not that, then turn off the parking lights and have someone press the brake pedal. Again, check that all are on and the same brightness. If the warning doesn't trigger until you do press the brake pedal, then probably the filaments of one of the bulbs are shorted together.

This all assumes that you have OEM or OEM equivalent bulbs. If you have switched to LEDs, then you'll get warnings if the correct load resistors aren't wired in correctly.
 
joegr said:
This comes up every so often on here. Every time, the claim is that all the bulbs are working, but every time eventually, it comes out that one of the filaments of one of the bulbs really is out. The brake lights are dual filament bulbs. Turn on the parking lights, and verify that all bulbs are lit, and that all are the same brightness. If one is dimmer or brighter than the rest, it's your problem. Also, be sure to check the tag lights. If not that, then turn off the parking lights and have someone press the brake pedal. Again, check that all are on and the same brightness. If the warning doesn't trigger until you do press the brake pedal, then probably the filaments of one of the bulbs are shorted together.

This all assumes that you have OEM or OEM equivalent bulbs. If you have switched to LEDs, then you'll get warnings if the correct load resistors aren't wired in correctly.
Click to expand...



I switched to LEDs on the brakes, which is what autozone claims is out. Intitally a bad brake light really did cause a lamp out message, which is when I made the switch to LEDs. Another curiosity is the LEDs appear to remain on for a longer duration of time than the previous lights, though they seem more to be "glowing" then fully on. I've thuoght about going back to OEMs to see if it solves the problem.

Sometimes -- rarely -- when I have my foot on the brake the lamp out will quickly switch on and off a few times, which causes an annoying flurry of service "beeps" too.
 
bulb check system does not include plate, third top mount brake and front bumper corner amber turns. ask me how I know.
 
I am so glad this was posted, I just started having the same problem. Just replace the bulb that it indicates I see. Mine still work as well and I couldn't really tell if one was dimmer or not. Sounds trivial really which is a relief because mine started to come on when I have to jump on my brakes with all the force I could muster to avoid becoming a permanent fixture of a 2012 Ford F350 last week.
 
bulb check system also does not care about the back up bulbs.
 
perpetualchange said:
Not sure. Would it really matter? I bought whatever the guy at autozone sold me after being told what model I drive.
Click to expand...

The LS is a switched ground (negative) system. Many cars are a switched positive system. LEDs that work on switched positive systems generally won't work on switched negative systems. The problem comes from the way the parking light and brake light functions are combined in the LED assembly.
 
Well, they work, as in they light up. Not sure if that would or could cause anything funky to be going on electronically.
 
Are you sure they actually work?

As in they are brighter when the brake is pressed? I have a hard time believing any bulb from autozone is wired correctly to work on the LS.


I bet you only have parking lights, and when you press the brake pedal - that is when you get the error message. Thus you have no brake lights other than a 3rd brake light.
 
perpetualchange said:
Not sure. Would it really matter? I bought whatever the guy at autozone sold me after being told what model I drive.
Click to expand...

the guys at autozone asked what car your drove so that he could get you the right sized bulb, that doesn't mean that it will work right with the cars systems

some LED bulbs have resistors built in and will fool the bulb check system into thinking that a bulb with a good filament is in the socket, most LED bulbs do not, and the LEDs do not have the same resistance that an incandescent bulb has and with trip the bulb out message even if the bulb does light up. if your really sure that all of your bulbs are lighting up as they should, then i would start with adding a set of load resistors
 
I'm sure. After half a year of this + high volume highway traffic everyday I also would have been plowed into by now if they weren't working.

What's a load resistor?
 
LED-Bulb-Load-Resistor-50W6RJ.jpg


power-resistor-20w-8r-sqp.gif



example only:
[video=youtube;5yKlQQCMbwg]http://www.youtube.com/watch?v=5yKlQQCMbwg[/video]

example only:
Resistor_wiring_diagram.png




I got as far as purchasing them, then yanked the LED's out and forgot about the idea.
the Amber turns were severely misbehaving. Never got around to a re-attempt.
 
I don't have those fancy led bulbs like you guys but I figure I would update in case someone searches this thread.

I had the "Check left brake lamp" warning coming on intermittently and it was only when I pressed the brake. However, every time I checked them, they functioned completely like normal, no dimness, nothing. Everything seemed fine. I replaced the bulb and the warning is gone. The old bulb looked completely functional and nothing seemed out of place.

I don't get it, but I fixed it. :confused:
 
words of warning: load resistors get damn hot!

I only have LED turn signals, and after the blinker has been on for a minute or two (with it flashing of course) they are almost hot enough to burn. if using, you need to be careful where and how you mount them as to not start a fire or burn the carpet in your trunk (i have seen the second from a kid just wiring them up ant tucking them under the carpet for his parking lights)
 
Any details on size of load resistor that worked for you on the turns Loud ?

I picked up a small selection but as stated never got around to revisiting.
 
sorry, no details. just walked in to an O'reillys and bought the only set they sold.

they look exactly like the gold aluminum pair you posted a picture of.
 
lol, yup! same here, early spring this past. Enough of that BS.
 
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