Intermittent display of bulb out indicator on dash display

[davidwhite]

Sorry if this has been done before but I can’t find what I’m looking for in the archives

 

I vaguely ( it’s old age creeping up ! ) remember reading that this symbol also meant something else if all the bulbs were fully functional but I can’t remember what it might indicate 

I get the light come on every now and then never two start ups on the trot but it has come on twice in the last 10 or so start ups, when it illuminates it says on until the ignition turns off 

any help much appreciated 

thank you 

[satire111]

When I've had this in the past its been a bulb that  the glass has gone either black or silver, not sure why the glass does this but the filament of the bulb is becoming more resistant and that's what the bulb out warning system system looks for I have often found it to be the side light bulbs or the twin filament bulbs in the rear good luck and let us know if you find the problem 

[pikpilot]

Also happens with the DRL bulbs. They are a special bulb to resist vibrations breaking the filament, but my experience is that the solder contact pip on the end of the bulb is fretted away by vibration. Result is that as it wears away it makes intermittent contact, resulting in random self fixing warnings of bulb failure. I posted a photo of a fretted bulb in a thread about three years ago.

if this your problem, fix it by adding more solder to the end of the bulb. Mine is still working fine but I did both sides while I was at it.

[xman]

In my experience, on the mk 2 estate a common culprit is the rear high level light which is a string of LEDs. It can be intermittent, either going off completely, or flickering at low light, or partly out. Due to solder joints going dry (the unit connector is two pins soldered directly onto the pcb) or water ingress/corrosion. A light tap with your hand can sometimes restore it or knock it out for a while. They are about £40 for a replacement. Requires removal of the tailgate trim, (lower, then upper) which is a bit of a faff and prone to breaking the molded clip mounts on the plastic trim parts, particularly on the upper narrow piece, so take care.

 

Some members have been able to open up their sealed units and repaired the PCB. I couldn't open mine (my2012 estate) and I'm pretty good at that kind of thing.

 

The dash light coming on will coincide with application of brake. If you had maxidot you would get a text message "check 3rd brake light"

Edited 10 July, 2021 by xman

[Guest]

@xman

 

On a PFL Mk2 the high level brake light isn't monitored so nothing shows on maxidot.

[xman]

19 minutes ago, MicMac said:

@xman

 

On a PFL Mk2 the high level brake light isn't monitored so nothing shows on maxidot.

 

OP has a 2009 FL estate according to his profile.

[Aj77]

I've got the bulb light on in dash. Turns out it's the right full beam. If I wiggle the bulb in its socket I see some small sparks, or arcing, then the light goes off but usually comes back on after a bit. So it could be a lose connection or short somewhere. You have to check every bulb on the car including all the interior bulbs also in boot, reg plate etc, there's quite a few of them.

[davidwhite]

Thanks for the replies and info content 

I’ve checked every bulb each previous time the light out bulb has illuminated every one is fully functional including the high level break light 

I don’t have maxi dot display ( or at least full info display ) which I think was optional, 09 facelift elegance model 

however

since I changed the tailgate I’ve no boot interior lights ( issue with micro switch on lock ? I believe but it’s a faff to remove the trim I’ve been warned ) however common sense says that if those lights out were causing an issue the warning bulb would be permanently on ( and I’ve had the warning bulb occasionally before the tailgate was changed 

 

I vaguely recall reading the warning bulb could be linked to something else if all lights proved functional ( faulty glow plug or injector maybe ?? ) thought I read it on here but ........

[Aj77]

9 minutes ago, davidwhite said:

Thanks for the replies and info content 

I’ve checked every bulb each previous time the light out bulb has illuminated every one is fully functional including the high level break light 

I don’t have maxi dot display ( or at least full info display ) which I think was optional, 09 facelift elegance model 

however

since I changed the tailgate I’ve no boot interior lights ( issue with micro switch on lock ? I believe but it’s a faff to remove the trim I’ve been warned ) however common sense says that if those lights out were causing an issue the warning bulb would be permanently on ( and I’ve had the warning bulb occasionally before the tailgate was changed 

 

I vaguely recall reading the warning bulb could be linked to something else if all lights proved functional ( faulty glow plug or injector maybe ?? ) thought I read it on here but ........

 

I assume you've checked all the lights front and back, main beam, full beam, side lights, indicators etc?

 

My mistake was checking the full beam when it was too light outside, it's easy to miss something. 

[xman]

IIRC, once the bulb warning light comes on, it remains on until the ignition is turned off. So even a short intermittent fault will trigger the warning and it stays on until the engine is restarted. As most bulbs are filament bulbs, its likely that once one blows, thats the end of the bulb. So that leaves the high level brake light which can IME be intermittent. It could also be a corroded or bad bulb connection or a loom issue, you'll need to go round and check every bulb and connector in turn.

 

Maybe if you buy a cheap OBD reader (from £15} and read the error code when the warning light is on it might tell you which light is to blame, not sure.

[Aj77]

The cheap reader didn't pick up the light for me, but I've ordered a carista adapter and will tell you if it picks it up on Tuesday if I remember .

[Guest]

2 hours ago, xman said:

 

OP has a 2009 FL estate according to his profile.

I saw that and was merely stating what I know from experience and in any case thought the OP may have one of those late/early model Frankenstein builds since I don't know exactly when the Mk2 FL was released or how hybridised the changeover was.

[davidwhite]

Thanks for the further input 

a ) I’ll double check all the bulbs again 

b ) I’ll ask tame garage owner if I ( we ) can plug it into his reader 

c ) I’ll check the warning light does indeed go out following turning the ignition off ( I’m pretty certain it does )

 

i leaning towards thinking that as the boot interior lights aren’t turned on when the tailgate is opened that the relevant micro switch isn’t functional thus the resistance of those two bulbs has been bypassed long term therefore the recognised ‘ normal ‘ all bulbs healthy resistance value has been compensated ? 

 

Might just have the car read for any fault codes stored then do a reset and recheck after ( if ) the warning bulb comes back on 

[Aj77]

58 minutes ago, davidwhite said:

Thanks for the further input 

a ) I’ll double check all the bulbs again 

b ) I’ll ask tame garage owner if I ( we ) can plug it into his reader 

c ) I’ll check the warning light does indeed go out following turning the ignition off ( I’m pretty certain it does )

 

i leaning towards thinking that as the boot interior lights aren’t turned on when the tailgate is opened that the relevant micro switch isn’t functional thus the resistance of those two bulbs has been bypassed long term therefore the recognised ‘ normal ‘ all bulbs healthy resistance value has been compensated ? 

 

Might just have the car read for any fault codes stored then do a reset and recheck after ( if ) the warning bulb comes back on 

The lightbulb light should go out when the fault is fixed so no point in resetting  as it will just come on again. 

[pikpilot]

I use a cheap ELM diagnostic interface (WiFi) connected to an iPad running Carista to find out which bulb is causing the problem. Never fails.

[Aj77]

Carista picks up the light fault. Nice piece of kit.

[Nepomuk]

I had an intermittent bulb failure warning on my 2012 Octy Estate. It was fixed ( a couple of years ago) by fitting a new body control module. It wasn't cheap. but it has worked.

 

[davidwhite]

Annoyingly the bulb light came on again this morning but extinguished when it stopped and didn’t come back on when I restarted the car to do return trip 

I’ve got no other ( obvious ) faults

my local tame garage owner is retiring very soon I may bite the bullet and get a full health check done ( on the car that is 😀 )

cars about to clock 100k and it’s now 12 years old so it’s really in the ‘ make your mind up time ‘ stage 

run it until it dies or buy newer but unknown car ?

Edited 18 July, 2021 by davidwhite