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No juice to centre console...

FactionOne Jan 1, 2006

  1. FactionOne

    FactionOne Administrator Staff Member Administrator

    Hi folks,

    A bit on the long side this one, but I'd be really grateful if you could spare a few minutes and read through it as I'm pretty stuck, it's a ridiculously trivial fault, and I've just got the freedom to drive around with some music whenever I feel, and I can't!!!

    I'm having a bit of a nightmare at the moment... I've got a little bit of a power issue at the moment... I noticed on Friday night that my Road Angel wasn't getting any power; it's hard-wired into an ISO adapter for my stereo. I didn't have my amps/speakers connected at the time, so I could only check the function of my stereo by observation of the eject-button on ignition... I noticed that didn't light either.

    Figuring I'd just somehow caused a simple electrical gremlin when I had to disconnect/reconnect the battery a few times on Friday, I decided the RA and stereo weren't essential at the time and thought no more of it...

    Anyway, I came to reconnecting my amps/speakers yesterday, everything's back in and I made certain to take great care (I don't plan on adjusting any of the audio kit again for a LONG time); and I'm as positive as I can be that all the power and signal wiring for my amps/speakers is fine. I decided I'd whip-out my head unit before reconnecting the battery and trying the stereo and RA again... Everything looked fine, I couldn't see anything disconnected or in a situation where it might be causing a short.

    Just for good measure I disconnected the ISO speaker-block from the back of the head unit (everything's on RCAs to amps now); and I removed the block that has connections to a line-in I have in the glove-box for iPods/MP3 players that are visiting the car, and the EQ calibration microphone.

    ...By this point I've got a good feeling, all the wiring in the car for audio hasn't been this well checked since I put it in... I reconnect the battery and turn on the ignition...

    ...I hear no "Raaaaaaaahd Aynjul!" and there's nothing doing on my stereo.

    I popped off the end of the dash, the Radio fuse looks fine (swapped it anyway with no effect), and I had a look at a few others (reason follows); and they looked OK. In the hope that there was some dodgy ground somewhere around the stereo, I decided to disconnect the HU and just see if the RA came to life... Nothing.

    So I'm at a bit of a loss for ideas really, I can't see that there's anything complicated at the cause of the problem, because things just stopped working all of a sudden. I was fettlin' on Friday, but I disconnected power and signal from, then removed my amps (no un-insulated power cables left flapping around or anything like that). I also cleared an airbag light; and I reset my service indicator (just reset channel 2 on the instrument cluster).

    There is one other issue I've noticed since Friday, again something I can't figure out (and why I was checking more fuses as mentioned earlier); My dome light is behaving rather strangely... If I get in the car, the light is on, but it stays on after I light-up the ignition (when as you know it should dim to off immediately), until I open and close the drivers door again. I started to think that this was maybe a dodgy door switch issue (as it's so common), but you can SLAM the door first time, and close it with a feather's touch the second time, and the result is the same. Also if I turn my headlights on, I don't get a warning, so the car does know the door is shut. It's just the dome-light is being stubborn for some reason. I don't know if it's the same gremlin causing stereo issues, but maybe? (I'll reconnect the laptop in a little while and check the door switch function by reading the measured value blocks for the central locking control unit, but I'm 99.9% sure I know the outcome of that test given my aforementioned observations...)

    PLEASE PLEASE PLEASE... <u>ANYTHING</u> you can think of that might help me figure this out would be greatly appreciated...


  2. AndyMac

    AndyMac Moderator Staff Member Moderator

    Is the RA wired to perm live or ignition on?
    I'm guessing ignition on, so I'm assuming your car has an ignition on wired to the power ISO for the stereo as some later Audi's use the CAN-BUS for this function, so there is no wire in the ISO for it (3rd one along from the ground wire).
    IIRC the fuse for the RADIO is the perm live feed, and I take it you have perm live to the radio, it's just the ignition on that's playing up?
    The Ignition on feed is protected by a seperate fuse called Radio S-Kont in the manual. Also double check the manual against the lid of the fuse box for the location as they don't always tie up.
    If this all checks out then check you have 12v feeding the S-Kont fuse, with the ignition on, obviously. If that's OK then check again with a 12v testing screwdriver/multimeter that there is no 12v at the ISO connector.
    If there is no 12v at either side of the S-Kont fuse then you'll need to trace it back probably to the ignition switch, but if this is the culprit then I'm surprised that anything works in the car.
    If there's 12v at the fuse but nothing at the ISO then I'd just run a new cable from the cold side of the fuse to the ISO as I don't know how torturous a route the wiring takes.
    I can't see how it's related to the door switch problem, but you never know.
    When did this problem arise? Was it immediately after you installed the amps? If so where did you ground the amps? I've seen some very bizarre things happen when I moved the ground for the rear light cluster to a different location that wasn't a perfect ground.
  3. Broken Byzan

    Broken Byzan Photographic Moderator Staff Member Moderator VCDS Map User quattro Audi A4

    HHmm i cant see how all these faults are all linked, unless it's some kind of earth fault,

    It would appear that if the faults all started together it really has to be something wired to ground that shouldnt be, or something is wired backwards allowing power to track where it shouldnt, hence the light etc staying on. Very hard to diagnose without seeing
  4. FactionOne

    FactionOne Administrator Staff Member Administrator

    Well folks, I managed to fix it earlier tonight (yes, tonight, I've just got in - can't you tell I'm enjoying all this way too much!)...

    ...Before I get on to the staggeringly simple and equally annoying cause/repair; Andy, I forgot to mention mate, the RA was hardwired the lazy way... I had most of the dash trim off the afternoon I did it and didn't have any inline fuses handy. I did however have a multi-vehicle ISO adapter between the end of the Audi loom and the stereo HU. The adapter is basically wired as a straight-through 4 inch extension, how that makes it an adapter I've no idea, but I bought it to butcher remote and other wires into, saving me from having to make any modifications to the original Audi loom - this was obviously a perfect candidate to pinch some power from as there's an ignition live and it's already fused. ...Incidentally, if you're ever buying a pre-wired connector from Halfords (bare wires to a male or female plug), get a multi-vehicle ISO adapter, it's the same price and if you chop it in half you've got the bit you want plus the opposing portion gratis!

    Right, so back on to the topic, the RA and HU are connected to the same part of the Audi loom (ie same line after fusebox); meaning that either both lumps of hardware were faulty or there was definately just no juice getting into the pipe in the middle of the dash. As I mentioned in my previous post, I'd noticed odd things with the dome light, and figured that maybe the dome-light not dimming with ignition and stereo getting no power were perhaps linked, because I'd discounted the door switch from causing the dome lights' behaviour, as everything else that depends on the door switch functioning correctly was fine. So then, like you, I considered ignition sensing, but also like you, I decided it'd be too odd even for VAG to have one circuit detecting the key position for engine start, and another for interior ligting and audio etc., and perhaps another... and another. You just simply wouldn't expect anything to happen at all if the ignition switch was at fault...

    Interestingly, before I made any more positive progress, I noticed that my doors were no longer auto-locking at 15km/h - could this be part of the same problem? Did I even want to think about having something else to track down?!?

    ...I Then I thought about the fact that I could operate my seats when the ignition was on - I've retrofitted S3 recaros, and wired the seat-electrics to the relay-plate / bus-bar under the driver's side dash trim. Slowly the penny began to drop, the relay-plate / bus-bar is unfused (thus requiring the use of inlines, as with my seats) and working fine, the stereo HU and RA are on the same fused line and doing nothing. I started to drop thoughts of grabbing a multi-meter and VAG-COM and popped open the fusebox again...

    As I originally mentioned, I'd checked anyhing that mentioned Radio, Instrument Cluster, Convenience Equipment, Interior Lighting etc. - all with no effect. This time I was just about fed-up enough to remove every single bloody fuse, one by one...

    Andy mate, you're right, my owner's manual description of fuse locations has been trustable in the past, but in this instance, we find it's utter nonsense; I pulled a 10A fuse from location #37 (value and location from tired memory); and it was very very blown. I dropped a replacement in and guess what...

    /ubbthreads/images/graemlins/grin.gif Stereo receiving power. /ubbthreads/images/graemlins/grin.gif

    /ubbthreads/images/graemlins/grin.gif Road Angel receiving power. /ubbthreads/images/graemlins/grin.gif

    /ubbthreads/images/graemlins/grin.gif Dome Light behaving correctly - dims to off immediately at ignition on. /ubbthreads/images/graemlins/grin.gif

    /ubbthreads/images/graemlins/grin.gif Doors auto-lock above 15km/h again. /ubbthreads/images/graemlins/grin.gif

    ...And location #37 is described in my owner's manual as.............. V A C A N T............. Fritz the fool strikes again!!! (Rest assured, I'll be double checking which number was actually the fault tomorrow)...

    So in the end it was very simple to fix, but confusing that one measly fuse could cause so many odd things; and more concerning that now I know that if ever something electrical randomly stops working in future, I'm going to have to pull every single fuse to be absolutely certain that's not the fault given the inaccuracy of the handbook. Still, it meant I had some music tonight! (although I've got another issue now - a speaker or two intermittently cutting out, but I think that's down to a dodgy crossover)

    Thanks for your reading my mammoth posts (again!), and thanks for your replies,

    Cheers guys! /ubbthreads/images/graemlins/beerchug.gif

  5. AndyMac

    AndyMac Moderator Staff Member Moderator

    Glad you got it fixed Rob.
    For future reference the fuse locations seem to be pretty accurate if you follow the guide on the inside of the fuse cover. I found this out the hard way. I guess Audi produce the manuals way in advance of any changes then made on the production line - really helpful.

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