Engine Fault Workshop - Brake Light Switch

[jp101]

Hi All,

At a loss with this fault code -

 16955/P0571/001393 - Brake Light Switch (F): Implausible Signal
Possible Symptoms

    Malfunction Indicator Lamp (MIL) active
    Glow Plug Indicator Light active
    Brake Light(s) not working

Possible Causes

    Wiring and/or Connectors faulty
    Fuse(s) faulty
    Wrong Brake Light Bulb installed (21W instead of 5/21W)
    Brake Light Bulb(s) faulty
    Brake Light Switch (F) faulty

Possible Solutions

    Check Wiring or Connectors
    Check/Replace Fuse(s)
    Check/Replace Brake Light Bulb(s)
    Check/Replace Brake Switch (F)

Special Notes

    Brake Light Switches (F) have the reputation of breaking quite often.

VCDS is showing the brake switch as working, however my brake lights are permanently on with the lights turned on. Its on a 2005 MK5 2.0TDI, anyone know what fuses I should be looking at?

[doylebros]

You haven't just fitted any bulbs to your vehicle?

[jp101]

You haven't just fitted any bulbs to your vehicle?

nope! i did however have an intermittent power fault with the instrument cluster (which i've had repaired), and this fault appeared after i reinstalled it but i cant see how they are connected really. think its just coincidence.

[doylebros]

Fuse locations are vehicle dependant have a look at these drawings

https://docs.google.com/viewer?a=v&pid=explorer&chrome=true&srcid=0B4JrcYcfSOQGOGE0NTlkMjAtOGMwNS00Y2EwLWJmNTMtMmUxYzBjMjlhN2E0&hl=en_GB

[jp101]

Fuse locations are vehicle dependant have a look at these drawings

https://docs.google.com/viewer?a=v&pid=explorer&chrome=true&srcid=0B4JrcYcfSOQGOGE0NTlkMjAtOGMwNS00Y2EwLWJmNTMtMmUxYzBjMjlhN2E0&hl=en_GB

great! thanks :)

[doylebros]

Look at page 11 of 17 that's  say SC 12 30A fuse location drivers door area page 8 of 17

[Joesoap]

I think its fuse 11 blown ?

I have had a fair few now with the brake lights staying on
and the first one i had fun finding the fault.
Take a look at the clutch switch on the side of the clutch master cylinder for burning
it just clips off, replace and should sort it.

[jp101]

Ok, I've checked fuse 12 - is fine, there is no fuse in fuse 11.
 
I've noticed now that it is dark, as soon as the ignition is on (even with the lights turn off), the rear lights are on - as shown in pic

https://www.dropbox.com/sc/iywqknxxgx1igs8/IhjmnRxsQd

[doylebros]

Check fuse 13

[Joesoap]

Ok, I've checked fuse 12 - is fine, there is no fuse in fuse 11.
 
I've noticed now that it is dark, as soon as the ignition is on (even with the lights turn off), the rear lights are on - as shown in pic

https://www.dropbox.com/sc/iywqknxxgx1igs8/IhjmnRxsQd

it's going to be your clutch switch ....have you checked it yet .?

[jp101]

no, how does one go about checking that?

[doylebros]

Ok, I've checked fuse 12 - is fine, there is no fuse in fuse 11.
 
I've noticed now that it is dark, as soon as the ignition is on (even with the lights turn off), the rear lights are on - as shown in pic

https://www.dropbox.com/sc/iywqknxxgx1igs8/IhjmnRxsQd

it's going to be your clutch switch ....have you checked it yet .?

So your saying item 18 is faulty
http://www.partscats.info/volkswagen/en/?i=cat_vag_models&brand=vw&number=1714&set=1725&ein=2005&f=420&hauptgr=1234567890&hg=7&grf=072125409&bf=72125&hgug=721&ug=21&parent_id=2018423&detail_id=2018470

Or the wiring?

[jp101]

[/quote]

So your saying item 18 is faulty
http://www.partscats.info/volkswagen/en/?i=cat_vag_models&brand=vw&number=1714&set=1725&ein=2005&f=420&hauptgr=1234567890&hg=7&grf=072125409&bf=72125&hgug=721&ug=21&parent_id=2018423&detail_id=2018470

Or the wiring?

[/quote]

interesting, could i ask what makes you think its that? many thanks

[doylebros]

Well I've got to give it to JOESOAP 

The link below show how much effort another owner has put into solving this fault!


http://www.vwaudiforum.co.uk/forum/archive/index.php/t-141312.html

This is an extract from that(last post):-


Well after spending a good few hours re examining things me and my mate have temporarily sorted the brake light issue :)
Was going through all the fuses again and discovered that fuse 7 in the engine bay box (feed for brake position sensor and clutch switch was blown even though i had replaced it before. Tried another fuse and had another mate stood at the back of the car brake lights went off for a second before the fuse blew.
So we connected up a fuse saver circuit breaker and the five amp trip was going in an instant when it did stay on briefly a wisp of smoke from the rear of the engine bay could be seen.
So i disconnected the clutch switch again and breaker doesn't trip - wiring to the switch looks good we seem to have a short in the clutch switch.
Will have a better go at checking that tomorrow i am off for a celebratory pint :)

So he may of saved you a lot of time cause drawing No 65/18  I would of went for either module J519 or J220

So disconnect that switch find the blown fuse and your brake lights will function!

Part required 1K0 927 810 D - £61.38 full retail inc vat depending on your chassis number!

[jp101]

great thank you sir! i'll check it out tomorrow morning