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Please help! brake lights stuck on, fuse blowing! a3 2.0 tdi 2004 8p

Discussion in 'A3/S3/Sportback (8P Chassis)' started by chrisy t, Jan 7, 2012.

  1. chrisy t
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    chrisy t Member

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    [Jan 7, 2012]
    Hi guys, got a similar thread on here already but this is just regarding my brake lights. I recently had the coil symbol come up on the dash and my brake lights stuck on, even when i turned the car off the brake lights would stay on, however i ran a scan through vcds and it came up with implausable signal brake switch, so i got a new switch and fitted it and still the same thing, its only about 2 hours ago i went out to the car because it was doing my head in, i went into the engine bay and noticed that the fuse for the brake switch had blown, i changed the 5 amp fuse and put a 10 amp in and as soon as i changed it and turned the car on, it blew again! Could it be that i have a faulty brake switch? Would the fuse keep blowing if the switch was faulty or have i got a serious problem on my hands? Has anybody experienced this? Basicly my audi is out of bounds because i cant drive it with the brake lights stuck on, Would really appreciate it if somebody could help me.

    Cheers
    Chris
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  3. paddy
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    paddy Audi=No fault code, no idea

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    [Jan 7, 2012]
    What is the fault code. ?
    Is it the brake lights on the car and the brake warning on the dash ?
    If you take the bulbs out does it still blow the fuse ?
    Are you getting a fault code for ABS ( pump?)
    Have you tried blocks with VCDS ( around 60-66 from memory ?)
    Last edited: Jan 7, 2012
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  4. mike foster
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    mike foster Fossie VCDS Map User

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    [Jan 7, 2012]
    Take the brake switch out altogether and see if the lights are still on. If they are then you have a short somewhere. If not then clear the fault with VCDS and try again.

    Never put a higher value fuse in a circuit than the designed rating, it can cause the wiring to catch fire.

    ​Sorry to say this but if you do not have electrical knowledge (and I assume because of the fuse thing that you haven't) then you should get the car to an expert for fixing.
    #3
  5. chrisy t
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    chrisy t Member

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    [Jan 8, 2012]
    I toake your point onboard Mike, cheers, i know i do know a little about the electrics, i also know that you shouldnt use a higher fuse, it was the only one i had and i didnt expect the fuse to blow because i was certain it was the switch, coil light is flashing on the dash, When i plug the switch out the brake lights turn off which i think is a good sign! I have a new swithc now, its the newer one that replaced the old finicky one! i will replace the fuse along with the swith tomorrow and see if it fixes it. Thanks for the advice also paddy, if the swithc doesnt work i will try taking out the bulbs, i have got a fault for rear right wheel sensor for the ABS AND ESP also, about a week ago both lights, ESP AND ABS were on my dash, fault was rear right wheel sensor intermittent.
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  6. ub7rm
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    ub7rm Member

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    [Jan 8, 2012]
    I presume Audi use the same type of switch as found on VW's but are you aware that there is a very specific procedure for installing the switch? Failing to follow the procedure will damage the switch and it will either not work at all or fail in the on position.

    iirc its as follows:

    Remove the old switch
    Push the brake pedal down to the floor, start the engine if you need servo assistance.
    Make sure the plunger is fully extened on the new switch and place it in the bracket but DONT LOCK IT IN POSITION
    Slowly bring the brake pedal up, keep holding the switch in position.
    Once the brake pedal is fully up twist the switch to lock it into position. Make sure there is a loud click, there is a fair amount of resistance just before the click.
    Connect the wiring.

    Job done.

    Sounds simple but if you just twist it without letting the brake pedal come up against the fully extended plunger you will break the switch internally. Allowing the pedal to come up against the plunger sets the 'off' position of the switch and twisting it till the click locks this in place.
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  7. chrisy t
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    chrisy t Member

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    [Jan 8, 2012]
    i have fitted the new switch today and i have now realised it is not the switch that is the problem, although vagcom says brake switch, everytime i even turn the key once in the ignition the fuse for the brake switch in the engine bay blows, i have gone through 5 fuses today just trying it, it is not the switch that is faulty, anybody any ideas? the brake lights just stay on constantly, here are the fault codes i get when i run a scan:

    1 Fault Found:
    16955 - Brake Switch (F): Implausible Signal
    P0571 - 000 - - - MIL ON
    Freeze Frame:
    RPM: 0 /min
    Torque: -98.0 Nm
    Speed: 0.0 km/h
    Load: 0.0 %
    Voltage: 11.55 V
    Bin. Bits: 00000000
    Torque: 0.0 Nm
    Bin. Bits: 0 00 0

    2 Faults Found:
    00469 - Infotainment Databus in Single Wire Operation
    011 - Open Circuit
    Freeze Frame:
    Fault Status: 01101011
    Fault Priority: 3
    Fault Frequency: 1
    Reset counter: 33
    Mileage: 153063 km
    Time Indication: 0
    Date: 2012.01.08
    Time: 15:01:19

    00470 - Combination comfort Databus in Single Wire
    011 - Open Circuit
    Freeze Frame:
    Fault Status: 01101011
    Fault Priority: 3
    Fault Frequency: 2
    Reset counter: 33
    Mileage: 153063 km
    Time Indication: 0
    Date: 2012.01.08
    Time: 15:01:20

    1 Fault Found:
    00929 - LockingModule for Central Locking; Front Passenger Side (F221)
    008 - Implausible Sign

    2 Faults Found:
    00871 - Bass Speaker Front Right (R23)
    011 - Open Circuit
    Freeze Frame:
    Fault Status: 01101011
    Fault Priority: 5
    Fault Frequency: 1
    Reset counter: 33
    Mileage: 153063 km
    Time Indication: 0
    Date: 2012.01.08
    Time: 15:02:37

    00856 - Radio Antenna
    011 - Open Circuit
    Freeze Frame:
    Fault Status: 01101011
    Fault Priority: 5
    Fault Frequency: 1
    Reset counter: 33
    Mileage: 153063 km
    Time Indication: 0
    Date: 2012.01.08
    Time: 15:02:39

    2 Faults Found:
    00352 - Terminal 30A
    011 - Open Circuit - Intermittent
    00926 - Terminal 30
    011 - Open Circuit - Intermittent

    Sorry for the long list, its never ending! i cant drive the car with the brake lights stuck on. PLEASE HELP!
    #6
  8. paddy
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    paddy Audi=No fault code, no idea

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    [Jan 8, 2012]
    I have emailed nige, he might be able to shed a little light on this for you. My guess is you have a short outside the brake light circuit that is causing your problem, hopefully Nige will know what is at fault from your fault codes listed above, the problem is even the wrong wattage bulbs can cause a brake light switch code so its not obvious.
    My guess is you are going to need to run blocks to further pin down the problem.
    Hopefully Nige will log in later.
    #7
  9. imac83
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    imac83 New Member

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    [Jan 20, 2014]
    Hi Chris I have same problem did you get it fixed and how much plsssss tell me not lots £££££
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