Exterior Bulb Failure Indicator

[hamsters]

Hi, can anyone help with this one please! The bulb failure light came on recently and today got around to replacing the rear stoplight drivers side that had failed. However when i start the ignition the bulb failure light comes back on until i press the brake pedal when it will go off and stay off! However if I then turn on the lights the indicator will again come on and stay on ! on pressing the brake pedal the light will go off but come back on as soon as pressure on the brake pedal is released. If I turn the lights back off the failure light stays on - until I brake when it will go off & stay off! I have checked all the exterior bulbs in various combinations and I cant find any bulb that has failed! any help appreciated please <_y

[johnb80]

Replace the other brakelight bulb OR check the earth on the rear light clusters. I suspect what is happening is that when you don't have the lights on, the brake light is coming on and it's return to earth is via the sidelight circuit (back feeding). When you put the sidelights on that path is no longer available and you get the warning. Switch the sidelights on and get someone to press the brake pedal, my guess is that one side wont work as it should, this side has the bad earth.

 

Often unplugging the cluster, a quick spray with WD40 and then connect/disconnect the plug a few times will solve the problem.

 

Good Luck - John

[Ivor_E_Tower]

Agree with John - and do make sure that both rear brake lamps are working correctly now - not a duff bulb with the rear lamp and brake lamp cross-wired? Check lighting intensity when you get someone else to press the brake pedal.

[seatkid]

You might have put the wrong bulb in or the wrong way round. Check the bulb you fitted was the correct type for the position (single or dual filament) and (offset or no offset pins). If its a dual filament bulb that should be and is fitted, check its in the right way round.

 

Check with the other side if youre not sure...

[Ogben Schmutzel]

Incredible

[Guest vr6galaxy]

the faulty bulb warning light always comes on when I start up. I have not sussed out when exactly it goes off because sometimes it is when I press brake pedal,

Thats what it's meant to do! it can't see the brake light bulbs untill you comlete the circuit by pushing the switch

[johnb80]

You might have put the wrong bulb in or the wrong way round. Check the bulb you fitted was the correct type for the position (single or dual filament) and (offset or no offset pins). If its a dual filament bulb that should be and is fitted, check its in the right way round.

 

Check with the other side if youre not sure...

Sorry, don't agree with your logic, it wouldn't trigger bulb failure only when the lights are on ???

 

Taking the first situation the bulb the wrong way round, that can't be done due to offset pins but even if you did manage it you would get bulb failure straight away. In the second case, single filamenty bulb fitted into dual filament holder, again difficult due to offset pins, it would short the brake and tail light circuits together, I'm pretty sure this again would trigger the fault straight away.

 

Regards - JB

[hamsters]

many thanks every one for the input - I will try out the suggestion tomorrow and let you know how its gone :o

[Masked Marauder]

With a twin filament bulb the filament can break at one end and drop onto the other filament and earth through there. When the lights are on the resistance is wrong, so you get the check lamp coming on.

[seatkid]

Taking the first situation the bulb the wrong way round, that can't be done due to offset pins but even if you did manage it you would get bulb failure straight away.

Should be difficult, but it can be (and has been) done! If the high wattage filament is on the park circuit and the low on the stop, maybe the bulb check is getting confused or fooled as the current levels (and change) is wrong.

 

If hes fitted a single filament bulb in a two filament socket, then the symptoms described would probably occur. He should check brake light operation with side lights on..

 

Also he should check his number plate and high level lights are fully operational.

[johnb80]

We'll have to agree to differ on this one! If the single filament bulb was fitted it would make no difference lights on/off, you'd get the fault straight away in my humble opinion!

 

If the bulb failure works on current sensing then having the side lights attached to it would double the normal current straight away, if it works on current balance then the same would still trigger the failure. No doubt hamster will get back to us and let us know.

 

Regards - JB

[deadpool2e]

im having this problem now. changed rear stop tail light and all bulbs work, however oneside is brighter than the other . do you think changing the dim bulb will help??

[johnb80]

YES

[havikkk]

Hi guys.

This is my first post and in fact this is the reason that I joined the forum.

I was going to start a new thread until I found this topic had already been posted. I changed a bulb on my rear side light and get the same problem. The dashboard light stays on until I have pressed the brake pedal.

Can anyone help as I dont think a difinitive answer to the problem was posted previously.

Thanks.

[adrianf.]

Its because when you press the brake pedal the systen checks the brake light bulbs. Until this point it doesnt know if they are working or not

 

Adrian.

[mumof4]

Dont worry havikkk, its perfectly normal.As adrian says, soon as you touch the brake pedal it will go out..time to worry is if it doesnt...

 

welcome by the way.

[big_kev]

Can anyone remember which circuits the bulb warning indicator actually checks.

 

I know it doesn't check sidelights and I don't think it checks Foglights.

 

Does it just check front dipped/main beam and rear stop/tail ?

[havikkk]

Thanks for the replys guys. I was just thinking though that when I bought the car, the dash light was off and since I changed the bulb it is showing until brake is pressed. Why wasnt it showing at all initially as oppossed to now when it is showing even though all bulbs seem to be working?

[Tram]

And thanks from me too.

I have had this "problem" since i bought the car and have never managed to find out what the fault was. I must have checked the bulbs a dozen times in the first month.

Incidentally, my wife flung her arm up and hit the roof a short while ago and a storage box above the rear-view-mirror popped open. It's not a lot of use but nice to know these things exist.

ttfn Tram

[big_kev]

Incidentally, my wife flung her arm up and hit the roof a short while ago

 

Mine hits the roof on a regular basis... :lol:

[Smilge]

Can anyone remember which circuits the bulb warning indicator actually checks.

 

I know it doesn't check sidelights and I don't think it checks Foglights.

 

Does it just check front dipped/main beam and rear stop/tail ?

 

Kev it just checks the rear stop lights as there is an input from the same brake switch contacts to the ECU ...can't remember what it does but it's safety oreintated.

[galaxyfanboy]

Hi Guys - Just picked up my Galaxy today (53 plate Ghia Tdi) and I have some time to find all (if any) problems with the car - and googled for this "Warning light" issue.

 

I can confirm that touching the brake will extinguish this light instantly - so it must be a system check thingamee.

 

My first post - and "touch wood" I wont need to be asking too many questions with my problems!

 

 

Cheers, signing up has already saved me some rather confused time-wasting!