“Check Rear Fog Light” warning

[JamesGornell]

*New Octavia owner here and first post*

 

I intermittently get a warning on dash “check rear fog light” with the orange triangle + !

 

The warning only comes on after driving for about 10 mins. Then it’s gone again next time I start engine.

The drivers side (RHD/New Zealand) fog light seems to work and when checking the left there is a bulb there and the filament looks fine. 
 

Before I rip out the left bulb and grab a new one to try and fix this, has anyone else had this warning but the bulb wasn’t the issue I.e some kind of electrical fault?

 

In my experience I’ve only ever had 1 rear fog light and seen a few post here about dodgy bulb warnings. 
 

Im guessing I should just not be lazy and try a new bulb but starting a thread as it might save me a trip and 30 mins farting around. 
 

cheers

 

[nta16]

Hi, welcome.

 

I've had a check a brake light and I could find nothing wrong but I might have change the bulb anyway (I forget)I and sprayed electrical contact cleaner on the socket and wire loom connectors,  Then another time I noticed one of the (incandescent) daylight running lights was dimmer than the other then forgot about it as I rarely drive my wife's car, it took the car's computer a week to put up a warning by which time the bulb had gone the blackest I've ever seen a bulb so certainly there was some fault somewhere.

 

The car's VW computer can throw up all sorts of unexpected issues if the car battery is too low for it, even if the car starts and the lights seem bright enough and there are no warning symbols or messages.  This might not be the reason for your issue now but if the battery is low(ish), say below 12.2V/12.3V then fully recharge it just in case, an appropriate battery charger and maintainer is the best way to ensure the battery is fully charged (see 'Owner's Manual' for more details).

 

My advice, for what it's worth, is If your battery is low then just charge it up fully and see if the message returns, if the battery is OK then change the bulb (and clean socket and connectors) as it might just be the vibrations from driving upsetting the bulb, many modern made bulbs are poorly made so replace it with a better made one if necessary.  You may be able to see if the bulb is a factory fitted one if it has a date on it.

 

You could also post in the Octavia MK3 forum to see if this is a common problem with the model or not. - https://www.briskoda.net/forums/forum/235-skoda-octavia-mk-iii-2013-2020/

 

Closing advice - don't let the car battery get too low for the computers or they will make you suffer and if you read and before even doing simple jobs, like changing a bulb, refer to the 'Owner's Manual' you will know more about your model than many long term owners and some at garages and Dealerships.  If you've not got a paper printed copy you can download a free VWSkoda pdf copy from the following link. - https://manual.skoda-auto.com/004/en-com/Models

 

Some software updates perhaps from here. - https://updateportal.skoda-auto.com/

 

And perhaps any admitted (so few) Recall actions from here. - https://www.skoda-auto.com/services/recall-campaigns

 

HTH. 

 

[skomaz]

It won't be the battery. 

 

Just swap the bulbs over left to right and make sure the contacts are clean.  You'll only have one fog light on the drivers side at the back that is activated but the factory fit bulbs to both light units so you effectively already have a replacement spare. 

 

Even if the filament looks fine and is working it could be that it's starting to fail and the resistance is increasing which is enough to flag the error message

Edited 22 April, 2023 by skomaz

[nta16]

No I doubt it's the battery for this but as the car is new to James it's one of the many things it's best to check not too many sellers thoroughly check a vehicle when selling despite what some of them might say, plenty of threads and posts on here on that subject.

 

If there's a second unused bulb on the other side and using it resolves the issue then after a sufficient period of use to confirm this do throw away the bulb taken out so you don't forget and reuse it elsewhere and perhaps have the same happen again.  I can never understand why some people keep blown plug fuses and the like where you can't see they're blown particularly in with a stock of good plug fuses but some do.

 

[JamesGornell]

On 22/04/2023 at 22:02, nta16 said:

second unused bulb on the other side and using it resolves the issue

Swapped the bulbs over and everything works no more warning lights. 
 

I am baffled though because both bulbs are in working order. 

[nta16]

ETA: Thanks for reporting back.

 

1 hour ago, JamesGornell said:

I am baffled though because both bulbs are in working order. 

The VW computer systems want things they way they want best not to upset them, let your battery get too low for them and see how they react.

 

If the second unused bulb from the other side carries on working OK then do, after a sufficient period of use to confirm this, throw away the bulb taken out so you don't forget and reuse it elsewhere and perhaps have the same happen again.

 

Just had a thought, you could perhaps use the bulb the VW computer doesn't like in a vehicle that doesn't have all these computer overlords rather than waste a possibly functioning bulb.

 

I had a new (brake light) bulb be faulty and a different unused spare (brake light) bulb not work from storage, particularly modern made bulbs, over here at least, are cheaply made you have to buy a "heavy duty" or good make to the the standard quality of the past.  Someone in Tasmania told me he's just had to replace a bulb on his car for the first time in 17 years I don't think the replacement would necessarily last 17 years even if the car did.

 

Edited 4 May, 2023 by nta16
ETA:

[skomaz]

3 hours ago, JamesGornell said:

Swapped the bulbs over and everything works no more warning lights. 
 

I am baffled though because both bulbs are in working order. 

 

Both may be in working order but the resistance on one will have changed and increased due to age / use and it probably being close to failing.  The bulb monitoring system will have detected that and that it is above a certain threshold value and has therefore flagged the bulb out warning.

[Warrior193]

5 hours ago, skomaz said:

 

Both may be in working order but the resistance on one will have changed and increased due to age / use and it probably being close to failing.  The bulb monitoring system will have detected that and that it is above a certain threshold value and has therefore flagged the bulb out warning.

Another cause can be a slightly high resistance on the lamp holder contacts - removing and refitting the bulb can often be enough to clean the contacts. 

[JamesGornell]

The dreaded lamp warning came back within a week, both bulbs are definitely fine and working. 
 

next step get in and give it a proper clean with contact cleaner. 

[nta16]

21 hours ago, JamesGornell said:

next step get in and give it a proper clean with contact cleaner. 

Try cleaning the bulb, bulb holder and wires connection plugs with electrical contact cleaner and a brush and see how that goes.