Today checked all bulbs to find which one is causing the fault bulb to come up. Done the offside rear bulbs and all was ok, Nearside found the bottom bulb has got only a dim look to it on the smaller filament, the larger filament does not work at all ? I had all the lights on including reverse plus fog but do not know what that bottom filament is for. Its a 61 reg Elegance , any ideas chaps?.Bye the way all the fronts and dash are working.

that will be your fog but its not setup to work. You can turn it on in VCDS

that will be your fog but its not setup to work. You can turn it on in VCDS

I don't believe anyone has worked out how to do the twin rear fogs on a facelift with vcds yet?

Check the number plate lights, often missed but they are monitored by the blown-bulb warning system.

 

Also there are two smaller W3W bulbs on each side at the rear although I'm not sure these are monitored...

 

They are monitored on mine, had to change one on Sunday.

If its there why is it disabled I wonder?

If its there why is it disabled I wonder?

 

Cost to build. Skoda only have to knock out 2 units for all markets and then just have the firmware in the CECM set to LHD,  RHD or L&K. I suspect if you VCDS the car to be LHD the fog will effectively change sides.

 

Also looks nicer and symetrical, unlike, Fabias and Felicias

Fair point. But given wiring is there having them on for both sides would work for both markets anyway wouldnt it.

Ah ok that makes sense.

Skoda's stance towards the rear fog lights is interesting.

 

I buy into and appreciate the arguments / needs for single or twin rear fog lights but Skoda isn't consistent.

 

The MkII and MkIII Octavia's (despite being fitted / having the capability to run fog lights on both sides) only have one activated.

 

My MkII Superb however from the same era has two fog rear lights activated from the factory.

I would imagine on the estate yes at the tail / fog bulb is single filament so if the fog light blows so does the tail light so you should then get the blown-bulb warning.

 

I would be interested to see what the Maxidot error message would say, would it show both failed functions or just the one!?

 

On the hatch (twin filament bulbs) I guess you could be right Mike!

You have an interested audience here Mike!!

The faults are logged when differences from expected resistance are detected. In the single filament there are two states based on different voltages supplied and hence two different resistances expected depending on the switch. This can be used to determine the fault.

Not quite sure how the twin filament bulb works but my guess is that it is two circuits and regardless of the switch position, the same voltage goes through one or the other. With the bulb removed its open circuit either way and so the resistance change is the same, and regardless of the switch position, it is detected as the same fault.

The MkII and MkIII Octavia's (despite being fitted / having the capability to run fog lights on both sides) only have one activated.

 

Not sure about the MKIII, but IIRC one of the MKII L&K "factory features" was to have both fogs active.

 

If anyone's filddling with a BCM unit: does changing the lights to Tourist Mode flip the fog light?

Not quite sure how the twin filament bulb works but my guess is that it is two circuits and regardless of the switch position, the same voltage goes through one or the other. With the bulb removed its open circuit either way and so the resistance change is the same, and regardless of the switch position, it is detected as the same fault.

 

As an aside, it would be nice to know why the estates run single filament and the hatches dual. IIRC the single filament is a 12v "brake light" which has the voltage lowered to make it a sidelight. The other way round would drastically shorten the bulb life. I saw a hatch the other day with the top left side-light off, until ir braked, and then the sidelight lit (at sidelight intensity) along with the brake lights.

Fair point. But given wiring is there having them on for both sides would work for both markets anyway wouldnt it.

 

You'd think that, purely on promoting safety, that the maximum allowable for that market would be activated. Y'know, the old "we're doing everything we can" kinda thing

Certainly not on the preFL L&K's, I have activated a few L&K's with VCDS.

 

One of my neighbours has a 61 plate L&K Octavia estate, and that only has one fog light. Have tried, but there is no way of activating the second with VCDS.

 

Tourist mode simply flattens the headlight beam with a mechanical device inside the headlight, it doesn't have any effect on the rear fog light.

 

Mike

 

Hmm, I'll try and remember where I've seen that then :S

 

If tourist mode won't flip the fogs, then surely that would put the car at odds with foreign local legislation? (I'm assuming the French get fog too ;) )

Ah, another revenue generating scheme - pay the dealer twice!

These were the faults for mine when the wires were cut to the rear fogs. Interestingly even though the Left hand one can't be turned on it still shows as a fault!! Strangely it doesn't show right rear tail as a fault though ??

 

01506 - Bulb for Rear Fog; Right (L47)
            010 - Open or Short to Plus - Intermittent
             Freeze Frame:
                    Fault Status: 00101010
                    Fault Priority: 2
                    Fault Frequency: 254
                    Reset counter: 137
                    Mileage: 230145 km
                    Time Indication: 0
                    Date: 2014.12.22
                    Time: 18:09:35

            

01502 - Bulb for Rear Fog; Left (L46)
            010 - Open or Short to Plus - Intermittent
             Freeze Frame:
                    Fault Status: 00101010
                    Fault Priority: 2
                    Fault Frequency: 20
                    Reset counter: 137
                    Mileage: 230145 km
                    Time Indication: 0
                    Date: 2014.12.22
                    Time: 18:19:35

          

00984 - Left Tail Light (M4)
            010 - Open or Short to Plus - Intermittent
             Freeze Frame:
                    Fault Status: 00101010
                    Fault Priority: 2
                    Fault Frequency: 25
                    Reset counter: 132
                    Mileage: 230486 km
                    Time Indication: 0
                    Date: 2014.12.23
                    Time: 18:34:46

          

01506 - Bulb for Rear Fog; Right (L47)
            012 - Electrical Fault in Circuit
             Freeze Frame:
                    Fault Status: 01101100
                    Fault Priority: 2
                    Fault Frequency: 1
                    Reset counter: 97
                    Mileage: 235195 km
                    Time Indication: 0
                    Date: 2015.03.16
                    Time: 08:43:51

            

 

01502 - Bulb for Rear Fog; Left (L46)
            012 - Electrical Fault in Circuit
             Freeze Frame:
                    Fault Status: 01101100
                    Fault Priority: 2
                    Fault Frequency: 1
                    Reset counter: 97
                    Mileage: 235195 km
                    Time Indication: 0
                    Date: 2015.03.16
                    Time: 08:43:52

Edited 1 April, 201511 yr by Tinbum

One ball-ache you will find is that having replaced the bulb and the warning light goes out, the fault stays logged in the CECM. :S

 

Best to clear all errors when checking.

I thought this too.

 

On my vRS I had an intermittent failure of a brake light, just once the bulb failed, prompted the dash warning and (I assume) logged a fault.

 

The problem went away (both brake lights working fine) without changing the bulb but come the next service the dealer replaced the bulb for free.

 

I always presumed because he saw the fault logged and swapped it out as a preventative measure?