Hi There

I am looking at my daughters Fabia (2018) as she is getting the Third brake light warning message.

I have removed the unit and proved that it is working.

I have checked the No1 Fuse and its is OK

I have checked for power at the wiring connector but get nothing when the brake pedal is pressed.

This leads me to believe that the wire has a break in it.

If I was to run a fresh wire from the normal brake lights and make sure the earth is good ......the lights should work....but will the error message go away or have I bypassed something doing this workaround?

Trying to keep her spend to a minimum if I can so hence trying not to have to go to a Auto Electrical specialist.

 

Any help or guidance appreciated

Hi, welcome.

Quick thoughts.

Did you check earth supply as well as power?

If you can take off interior panels and get at wiring you could try a test supply  and test earth to see if the third brake light works and it turns off the warning (you might have to give the computers the old "off 'n' on agen" to satisfy them with the ignition switch but I don't know.

I've no idea of the wiring and connection points so also wonder if you'd be better repairing the break on original wire.

Have you checked connectors for issues?

I don't know if you could trace the break with an appropriate VW scan tool but with bidirectional you can certainly activate them.

Certainly for earlier cars you don't have to have the third light working but have to tell the MoT tester that you have disconnected it and probably get rid of the light on the dash which I don't know if this can be done with an appropriate VW scan tool.  You could ask or look on the 'Diagnostics & VCDS' forum. - https://www.briskoda.net/forums/forum/23-diagnostics-amp-vcds/ 

 

Someone now will probably be along here to say something like the wire(s) break in the conduit tube thing between body and rear door or yes run a fresh supply or you need to look at another fuse number, or any or none of above, hopefully not too long before they get here..

 

Good luck, let us know how you get on in the end.

  

@Edinburghskodarapid - Expanding on @nta16 above, does the other tailgate functionality all work?

Hi, welcome.

Quick thoughts.

Did you check earth supply as well as power?

If you can take off interior panels and get at wiring you could try a test supply  and test earth to see if the third brake light works and it turns off the warning (you might have to give the computers the old "off 'n' on agen" to satisfy them with the ignition switch but I don't know.

I've no idea of the wiring and connection points so also wonder if you'd be better repairing the break on original wire.

Have you checked connectors for issues?

I don't know if you could trace the break with an appropriate VW scan tool but with bidirectional you can certainly activate them.

Certainly for earlier cars you don't have to have the third light working but have to tell the MoT tester that you have disconnected it and probably get rid of the light on the dash which I don't know if this can be done with an appropriate VW scan tool.  You could ask or look on the 'Diagnostics & VCDS' forum. - https://www.briskoda.net/forums/forum/23-diagnostics-amp-vcds/ 

 

Someone now will probably be along here to say something like the wire(s) break in the conduit tube thing between body and rear door or yes run a fresh supply or you need to look at another fuse number, or any or none of above, hopefully not too long before they get here..

 

Good luck, let us know how you get on in the end.

 

Many Thanks

 

 - I will try the testing of earth tomorrow as it was pouring here today and I just nipped out between cloud bursts!!

 

 - Will also check the actual connector as I only touched my meter contacts against the accessible contact metal.

 

@Edinburghskodarapid - Expanding on @nta16 above, does the other tailgate functionality all work?

 

- Yes everything else on the car works as expected

My guess would be that it is a sheared wire in the rubber trunking area. Sometimes you can feel a broken and “turned up” end/ends by manipulating the rubber trunking. When I’ve repaired this sort of fault, I’ve always drawn the broken end back into the main car body area and added in a length of wire so that both the joints are away from the area that gets flexed when the hatch gets opened/closed.

Hi There. Thanks. That sounds like a good suggestion. I will have a look this afternoon (weather permitting) and report back

Just for info, if you want to quote something the two ways I know of are, you can highlight the section you want as I have for with what Paws4thot has put, this brings up the 'Quote section' box which you click and it goes into your 'Reply' box or if you want to quote the whole post you can click the '+ Quote' and the whole post goes in your 'Reply' box.  As below.  HTH.- 

 

39 minutes ago, nta16 said:

Just for info, if you want to quote something the two ways I know of are, you can highlight the section you want as I have for with what Paws4thot has put, this brings up the 'Quote section' box which you click and it goes into your 'Reply' box or if you want to quote the whole post you can click the '+ Quote' and the whole post goes in your 'Reply' box.  As below.  HTH.- 

 

Thank you - must have been able to tell I was struggling with that

Right - I have proven that the earth is solid...so no issue there.

I have run an independent power to the brake light but although the brake light lights up the error message still exists....so the incomplete circuit must still exist causing the message.

I believe that the issue is that there is a break in the 12v wire around where it goes from car into the hatch. Like people have suggested.

 

I phoned a local auto electrical engineer in Edinburgh and he suggested it would be £45 to fix it. So I think I will take him up on that rather than me having to remove trim and do the search.

It will probably be a month or so until it is looked at as my daughter is a teacher and I have to work ir round school holidays.

 

I will keep you of progress as things happen.

 

Cheers and thanks for the help and guidance.

5 hours ago, Edinburghskodarapid said:

I have run an independent power to the brake light but although the brake light lights up the error message still exists..

Did you try turn the ignition on and off a few times or driving the car around the block, I'm not sure if this works but costs nothing to try, some things are a little sticky on the computers - but I'd have thought brake light warning would go off once sorted.  Note the high level is on a separate fuse to side brake lights.

 

£45 sounds very good.  If he has a VW appropriate scan tool get him to give you a full error codes report and after that delete any error codes showing to keep things as clean as possible with the computers.

 

Good luck, do report back, cheers.

 

11 hours ago, nta16 said:

Did you try turn the ignition on and off a few times or driving the car around the block, I'm not sure if this works but costs nothing to try, some things are a little sticky on the computers - but I'd have thought brake light warning would go off once sorted.  Note the high level is on a separate fuse to side brake lights.

 

£45 sounds very good.  If he has a VW appropriate scan tool get him to give you a full error codes report and after that delete any error codes showing to keep things as clean as possible with the computers.

 

Good luck, do report back, cheers.

 

I did try starting the car a few times but didnt run it round the block as I took the live feed directly from the battery - a bit "Heath Robinson"!!! I take it the computer is looking for a circuit and with the broken wire its not finding it so I would need to do a proper wire replacement of the broken wire to reestablish the circuit.

 

If taking the trim off in the hatch is easy I might have a go myself but for £45 I am not sure if it is worth the risk of me making it worse than it is or breaking the trim

57 minutes ago, Edinburghskodarapid said:

I did try starting the car a few times but didnt run it round the block as I took the live feed directly from the battery - a bit "Heath Robinson"!!! I take it the computer is looking for a circuit and with the broken wire its not finding it so I would need to do a proper wire replacement of the broken wire to reestablish the circuit.

Yes that's what I'd imagine.  I used the direct clean supply and/or earth off the battery terminals for testing items in my very old  car but that had never heard of computers (thank gawd!).

 

59 minutes ago, Edinburghskodarapid said:

If taking the trim off in the hatch is easy I might have a go myself but for £45 I am not sure if it is worth the risk of me making it worse than it is or breaking the trim

I've never taken any trim off my wife's Fabia, in theory it should be easy especially with a (or set) of plastic trim removal tools but I also didn't bother on a neighbour's 15 years old (newish to me) car as I didn't know the fixing points of the plastic panels and then reinstalling 15 year old plastic fixed lugs can have some jeopardy.  You seem very capable I'm sure you could work it out but I'd imagine at £45 the auto-electrician has has quick method of repair and provided he's good at his job and not using some "wally fittings" at £45 I'd leave it to him.