Bulb warning light on constantly

[ArtistsRifles]

Hi all,

We've just accquired our first ever Mercedes - a 1994 E320 estate and are extremely pleased with it apart from an annoying niggle with the accelerator pedal and the bulb warning light. Dealing with the bulb warning light - we've checked that all the bulbs fitted are working on the exterior lights OK; I say fitted because the hole for the rear foglight on the passenger (near) side is empty and there does not seem to be a contact inside. Putting a bulb in this socket just has the bulb rattling about loose. So the questions are:

1) Should there be a bulb in the N/S/R foglamp (if so - looks like we'll need a repalcement bulb holder..)

2) If this is not the reason the warning light is on what other reason can there be if all other exterior lights are working OK?? Is there a known "bug" with this sysem such as bad grounding, poor quality bulbs etc??

Thanks all,

Neil.

 

[sym]

Have you checked number plate lights ? (apologies if you have !)

The bulb light coming on can sometimes be a sign of a bulb about to go pop ... they are very sensitive to resistance (and occasionally poor quality bulbs !)

S.

 

[Howard]

Hi Neil.

As far as i am aware, all w124's only have one foglight, my coupe is the same....

Ditto what Sym has said about the bulbs. Check all the bulbs are seated properly, and the contacts are clean. I had this problem and it turned out it was a bad contact on my O/S front foglight bulb.

H

 

[Steve_Perry]

Hi all,

We've just accquired our first ever Mercedes - a 1994 E320 estate and are extremely pleased with it apart from an annoying niggle with the accelerator pedal and the bulb warning light. Dealing with the bulb warning light - we've checked that all the bulbs fitted are working on the exterior lights OK; I say fitted because the hole for the rear foglight on the passenger (near) side is empty and there does not seem to be a contact inside. Putting a bulb in this socket just has the bulb rattling about loose. So the questions are:

1) Should there be a bulb in the N/S/R foglamp (if so - looks like we'll need a repalcement bulb holder..)

2) If this is not the reason the warning light is on what other reason can there be if all other exterior lights are working OK?? Is there a known "bug" with this sysem such as bad grounding, poor quality bulbs etc??

Thanks all,

Neil.

1) Nope, MB have always designed their cars with a single rear foglight, for the UK the rear fog is located on the O/S/R (driver's side). The reason your N/S/R cluster has a bulb socket is because that's where LHD euro spec cars have their fog light placed.

2)Check all bulb connections and don't forget items such as number plate illumination lights. The failed light circuit can be notoriously sensitive, in the past I have had the dash light come on approx 4 days before the bulb in question actually failed! Also some people find Halfords brand bulbs can cause issues, whereas Bosch or bulb's sourced from the stealerships seem to locate and behave better once fitted.

S.

 

[ArtistsRifles]

Thanks foks!!

I'll have all the bulbs out tonight - including the number plate ones and check the condition of the contacts. Kind of assumed there was only meant to be one rear foglight when the bulb rattled around, didn't stack up against the build quailty of the rest of the car but it's always best to ask when starting from a position of total ignorance!!!

Neil.

 

[MB250TD]

When I had this problem on my W124, it was the tiny side light in the headlight unit used as a parking light- not an easy one to spot unless you test the parking lights (ie ignition off). You should be able to check which bulb brings the warning on: start with ignition off and trying each parking light in turn. Then turn ignition to position 2 and check side lights, dipped, main beam, then indicators, brake and reverse. If you check it at night againt a wall, it is fairly simple to see the reflections of working lights and spot a failed bulb. I had a further problem with the same symptom when by battery was fading, which only became evident some weeks later. So wise to get your battery checked too. Good luck.
Regards
John

 

[mark.t]

check brake light blubs as well

 

[AlexR]

Check that the spec of the bulb is exactly the same as the origional - slightly different wattage etc affects the resistance in the lighting circuit and can cause the light to stay on....