Rear fog light not working

[Tinbum]

I have just picked up a new S/H 2011 Octavia and the rear fog light/s don't work. The light on the dash illuminates and both bulbs are ok. I can't see anything much in the manual I have. 

 

Does anyone know is there a relay or fuse anywhere for the rear fogs?

 

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

             Freeze Frame:
                        Term 15 On
                    Voltage: 13.30 V
                        ON
                        ON
                        Term 50 Off
                        OFF
                        ON

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

             Freeze Frame:
                        Term 15 On
                    Voltage: 13.10 V
                        ON
                        ON
                        Term 50 Off
                        OFF
                        OFF

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

             Freeze Frame:
                        Term 15 On
                    Voltage: 12.25 V
                        ON
                        ON
                        Term 50 Off
                        OFF
                        OFF

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

             Freeze Frame:
                        Term 15 On
                    Voltage: 12.25 V
                        ON
                        ON
                        Term 50 Off
                        OFF
                        OFF

[JeremyAndrews]

Have you tried replacing the bulbs even if they look ok? I knocked a bulb when refitting my rear clusters that looked ok but stopped working. Replaced the bulb and it was fine.

[JeremyAndrews]

Also the fuse is drivers side under the wheel to the right where the door is. Should even have a sheet with fuse positions

[Tinbum]

Have you tried replacing the bulbs even if they look ok? I knocked a bulb when refitting my rear clusters that looked ok but stopped working. Replaced the bulb and it was fine.

Cheers,

 

Yes already swapped them to make sure.

 

There's no card in my car showing which fuse does what and I can't see any mention of a fuse in a downloaded owners handbook or downloaded workshop manual.

[JeremyAndrews]

If no one has by tommmorow I'll get mine out for a photo.

[Tinbum]

If no one has by tommmorow I'll get mine out for a photo.

Thank you. That would be useful.

 

I have just found I have a full wiring diagram hidden in the computer and there are no fuses etc between the body controller and the rear lights. I'll check continuity between the controller and the lights tomorrow and between the switch and controller and the I should then know where the fault lies.  

[Tinbum]

I've checked for continuity between the body control module and both rear light clusters and both wires have a break somewhere.

 

As this is an ex police vehicle I'm thinking they may have used the rear fogs  as warning lights and installed a changeover relay in the circuit. When selling they have removed police specific items and possibly not connected the wires back together.

 

Oh where to look???

[silver1011]

I passed an unmarked FL Octavia today on the A19, he was in a lay-by.

 

There were a pair of blue strobes in the rear window and the two rear fog lights were flashing on and off intermittently (left, right, left, right etc.).

 

There are dealers that specialise in converting police cars and also returning them to a civilian life, I wonder if a call to one of them would help to point you in the right direction?

 

 http://www.cmspecialistvehicles.co.uk/vehicle/police-conversions/

 

http://www.macneillie.co.uk/

 

These guys specialise in the lights and electrical systems...

 

http://www.grs-conversions.co.uk/

[Tinbum]

_{Thanks, Some good links there.}

 

_{With mine being an estate the fog light bulbs are also used as tail lights so I do really need to get both sides working to keep things balanced. I've not come across a (21w) bulb being used at two different intensities before.} 

[Tinbum]

Certainly sounds like the supply wires have been chopped to add extra equipment. Note what I said earlier though, you won't get the nearside fog working.

 

Mike

Hi Mike,

 

Yes realise that but it should work as a tail light though. I have another exactly the same with working fog and that does. (Loved the first one I bought so much I decided to get rid of my Golf and replace it with another). His and Hers matching cars now!!

Edited 17 March, 2015 by Tinbum

[Tinbum]

No just single fog on the other, both are FL, one on a 11 plate and the other a 61. They are exactly the same so it may be somewhat confusing. Think I will be putting a 'shark fin'  on one to make it easy to tell which is which.

[silver1011]

One of the strange quirks on the MkII Octavia, on the hatch the combined brake/tail and fog/tail are twin filament bulbs (21W/4W), the estate however has single filament bulbs to perform the dual functions.

[JeremyAndrews]

Emergency lights being removed should have affected the normal running of any lights (Against the law for emergency lights to affect the statutory lights) and a dealer doing decoms shouldn't really have sold it with any faults like that.

Give Terry at SV lights a call if nothing else. Great guys who commission and decommission cars. His techs might know if they've come across the issue previously.

My ex ambo octavia has no issues with statutory lighting and had rear flashing Fogs at some point. Depends on the control system too.

[Tinbum]

Emergency lights being removed should have affected the normal running of any lights (Against the law for emergency lights to affect the statutory lights) and a dealer doing decoms shouldn't really have sold it with any faults like that.

Give Terry at SV lights a call if nothing else. Great guys who commission and decommission cars. His techs might know if they've come across the issue previously.

My ex ambo octavia has no issues with statutory lighting and had rear flashing Fogs at some point. Depends on the control system too.

I bought the vehicle direct from auction and was quite prepared to sort out any problems out myself.

 

Its the second one I've bought and the other was pretty well perfect in every way. Oh, actually its the 3rd I've bought- the first was from a dealer that turned out to be a total conman but that's another story which has resulted in me loosing all faith in the police and numerous other organisations.

 

I'll try what you suggest and if that doesn't work I have one of those line tester machines- like BT use, so I'll try with that to see if I can find the breaks with that.

[Tinbum]

Found the cut wires within a couple of minutes of using the line tester. For future reference they were behind the cushion that's to the left of the rear seats. There's also lots of cut wires behind the left hand boot trim. It looks as if the harnesses are possibly done at manufacture.

 

 

 

 

[Tinbum]

Emergency lights being removed should have affected the normal running of any lights (Against the law for emergency lights to affect the statutory lights) and a dealer doing decoms shouldn't really have sold it with any faults like that.

Having looked at it now what they have done is cut each of the wires and inserted a diode. This would allow the tail/fog lights to work correctly. At the light cluster side of the diode they have also attached a wire that would have gone to the extra electrics that would have made the fog lights flash. The diode would be so that that wouldn't back feed to the cars body controller. On decommissioning the car I think the person doing it has mistakenly cut the wires in the wrong place and then cut them correctly but not bothered to repair their mistake.

 

I find it interesting that there is often talk about wire repairs and their resistance etc.  but the diode, which will add a resistance and voltage drop, doesn't throw up a fault. Perhaps they have different thresholds on different circuits e.g. to account for production variations in bulbs.

[JeremyAndrews]

With the way cars are going with faults now most of the stuff is nothing to do with the cars wiring. The new ones at work all have hideaways instead of flashing the fogs. Same with the headlights