[DashingDaryl]

I have been doing searches about the Bulb Out Indicator on our Dash Boards, but I haven't found an answer to my Question.

My indicator is on, but all my bulbs light.

I know the most common causes are the license plate lights and if you use a "brass" based light bulb instead of a "silver" one.

My questions are:
How does the system work? I heard it is based on resistance, not voltage. Is that true?

If the indicator comes on when you only have your running lights on and not your headlights on, does that mean your headlights are not the problem?

Does it check dashboard lights?

Does it do a check for a radio light bulb that goes on when you turn on your headlights?

Are there any interior lights that are triggered? (Glove Compartment, Door Compartment, Etc)

If you could answer any (or all) of these questions, feel free to Chime in.

 

[aam]

I bet that your cruse control is also not working.

Resistance.
I don't think that the headlights are in that system.

It is not the color of the bulbs, but the watts......
Stay away from the cheap bulbs.

Ck the signals, brake,parking, license lights.

Forget the interior lights.
Did you CK the third brake light?

Regards,
aam.

 

[mrelbe]

Albert is correct about the resistance of the bulbs which translates into current draw that is measured by the bulb integrity sensor circuitry.
So correct and matching bulbs are the order of the day.
The headlights are part of the system but not when in parking lights position. Sometimes the culprit is the rear marker bulbs.

 

[DashingDaryl]

One of my third brake lights are out, but I heard it does not check for that. Easy enough to fix though. Thank you for your knowledge

 

[bayhas]

The light monitoring system is triggered by external lights only.

steps to troubleshoot it:

1-start the car with the light knob on 0

2-let go of the break, then step on it again, if the warning light turns on, check your left and right brake bulbs. The 3rd brake light IS NOT MONITORED in R129.

3-let the brakes go, turn the knob to the first position, if the warning comes on, then check the 2 front running lights, rear running lights (on the side), 2 tail lights, and 2 license plate lights.

3-if the warning has not turned on yet, put the car in reverse, if it does come on, then one of the reverse white tail lights bulbs is blown.

4-if still no warning, turn the head lights, then pull the knob to turn the fog lights on.


keep in mind that having a bulb somewhere with the wrong WATTAGE WILL trigger the warning, if the bulb is less bright that factory specs.

for example, front indicator are 5w/21W. anything smaller will throw a warning...

Check sylbania's website, compare to what's actually in your car, and make sure you have the correct bulb, if you cannot find a burned up one...

 

[greygirl]

Bulb out monitor

Greetings,
I had the same problem with my "Bulb Out" indicator. Every time it came on I would get out and check only to find out all the bulbs were working. Albert told me to check the "Bulb out" module in the coffin.I removed the module and took it to a friend of mine that owns an Electronics Shop. He found two cracks in the circuit board. He repaired same and to date I have not had any more problems. Hope this is of some help

 

[aam]

Greygirl,

I forgot about that one.....
The module.

Regards,
aam.

 

[DashingDaryl]

Thanks! I will check all the bulbs are to spec.

Also, where is "The Coffin"? (Aka where is the headlight module located?)

 

[aam]

As many of you know I don't like to work hard.
Fill up your avatar, I had to go up to your first post to find the engine and year.......

It is located in the back of the front fuse box.
It is the largest module.
The coffin is on the opposite side.
(Cover with six screws.)

I had some problems with it years a go.... I lightly taped on the sides of it.
No problem since.

I must be a scary guy.
Maybe I scared the hell out of it? Lol.

Regards,
aam.

 

[jmerc6]

My indicator comes whenever I turn on my lights, but after a few minutes it goes off. I can't find any bulbs out either.

 

[mrelbe]

That circuit board in the integrity module is prone to have solder cracks. Quite easily seen and soldered once you take the cover off. I re-soldered mine on the 560SEL and no problems since.

 

[Roberto_L]

if you are driving with your headlights off, say day time, and suddenly your light failure indicator lights up, for sure it is the brake lights. Check out your brake lights. Usually it is the left brake light. I don't know why but after reading some of the problem here, often it is the left side. Next, if no lights comes up then, switch the park light. If the lamp failure indicator light up, check your park lights in front, back and plate lights and back up lights.

 

[560sec944]

In my car, the light will come on sporadically in the summer when it is above 100 degrees - I'll check the circuit board as with the heat that does sound like a solder short.