AvantSE Posted April 15, 2009 Report Share Posted April 15, 2009 I have a 2006 Passat with RCD500 stereo, built-in hard-wired hands-free kit, MFSW, and a VW amplifier under the passenger seat. Recently, there has been no sound whatsoever though the radio unit seems to work fine in every other respect. I have tried a substitute radio, and a different amp, but with no success. All fuses in the 3 fuse boxes seem to be OK. VCDS indicates ch.47 Sound System as present but it is not recognised/communicating. Just wondered if anyone could suggest what might be wrong before I have to take it back to the thieves at VW? Cheers, Chris Link to comment Share on other sites More sharing options...
AvantSE Posted April 15, 2009 Author Report Share Posted April 15, 2009 If anyone has a wiring diagram from the 2 plugs (green and grey) that go into the amplifier, I would be really grateful if you could let me know or email it to [email protected] I can find a ground and a permanent live to the amp, but seemingly no switchable supply which I assume it needs in order to turn on. Cheers. Link to comment Share on other sites More sharing options...
shark_90 Posted April 15, 2009 Report Share Posted April 15, 2009 Chris, there's no switched live, it is switched on by CAN signalling. Are you trying to repair the amp then? Link to comment Share on other sites More sharing options...
AvantSE Posted April 15, 2009 Author Report Share Posted April 15, 2009 I tried another amp, which made no difference. I had a feeling it might be CAN activated, though until I get a wiring diagram I am unable to see whether the signal is getting to the amp. What I still find odd is that the system was working one second, and not the next (similar to a fuse blowing). What I have discovered via looking on the net is that there are some additional fuses hidden away on some cars, which are not on the 3 fuse boxes we checked the other week. Link to comment Share on other sites More sharing options...
AvantSE Posted April 15, 2009 Author Report Share Posted April 15, 2009 Should have added, my version of ELSAWIN doesn't cover the late Passat so I have just ordered a new version which will hopefully help matters. Link to comment Share on other sites More sharing options...
AvantSE Posted April 15, 2009 Author Report Share Posted April 15, 2009 Just for my own future reference, http://www.big-partycentral.de/Bilder/Dynaudio_Passa_3C_Build.pdf gives the pin diagrams for the Dynaudio system... I wonder if these are the same as mine. On the green plug on mine I could only find 1 permanent live - on this diagram it appears there should be 3x 12v supplies. Link to comment Share on other sites More sharing options...
shark_90 Posted April 15, 2009 Report Share Posted April 15, 2009 The can wires are the Orange/Purple (Can High) and Orange/Brown (Can Low). Are you getting volts to that permanent live? Link to comment Share on other sites More sharing options...
AvantSE Posted April 15, 2009 Author Report Share Posted April 15, 2009 The one permanent live I know of (a thin red wire) is getting 12v. I am sure there must be more though, as there is a very thick red wire which I would assume is from the fusebox to the amp; this doesn't have any voltage (permanent or switched) but I need to confirm it is indeed meant to carry 12v. The only other thick wire is brown, and that is ground. I am hoping that the thick red wire is meant to be 12v live and that somewhere along the line I will find a blown fuse hidden away somewhere. Link to comment Share on other sites More sharing options...
shark_90 Posted April 16, 2009 Report Share Posted April 16, 2009 A big thick red wire has to be +12v mate.. the question is where could the fuse be?? Link to comment Share on other sites More sharing options...
shark_90 Posted April 16, 2009 Report Share Posted April 16, 2009 Is it worth connecting a wire to the positive of the battery and connecting it to the terminal of the big red wire that you're thinking of? Risky perhaps, but I can't see a big thick red wire being anything different, can you? Link to comment Share on other sites More sharing options...
AvantSE Posted April 16, 2009 Author Report Share Posted April 16, 2009 I reckon it should be 12v but I am going to see if ELSAWIN turns up and check the diagrams. As you suggest, if I can establish that is another power lead, I can run a wire with an in-line fuse to the amp and see if I can get it working. A customer of mine also has a Passat and seems to think he has seen an in-line fuse somewhere behind the glovebox area when he took his apart to look at an aircon problem. Hopefully he's right. Either way, Saturday is the day for dismantling. Link to comment Share on other sites More sharing options...
AvantSE Posted April 16, 2009 Author Report Share Posted April 16, 2009 I also noticed that on the grey connector on the amp (the green one had the earth and power leads), there are 8 pins all showing a permanent 6V; there are a further dozen or so pins that seem to show no voltage - I am assuming these are speaker outputs from the amp. Just wondering why there would be a constant 6v feed on 8 pins? Link to comment Share on other sites More sharing options...
shark_90 Posted April 16, 2009 Report Share Posted April 16, 2009 I don't know, but I guess they could be active speakers? Link to comment Share on other sites More sharing options...
PetrolDave Posted April 17, 2009 Report Share Posted April 17, 2009 Just wondering why there would be a constant 6v feed on 8 pins? 4 speakers = 8 pins. DC biased at the mid point of a 12V supply = 6V Which means that the speakers are driven by a balanced signal, so instead of getting a 12V peak-to-peak drive they get a 24V peak-to-peak drive. Result 4 times the power output! (since power = voltage squared divided by resistance) Balanced drive is one of the oldest tricks in an electronic designers book to get more power without having to increase the supply voltage. Link to comment Share on other sites More sharing options...
AvantSE Posted April 17, 2009 Author Report Share Posted April 17, 2009 You learn something new every day ! Fortunately someone very helpful has sent me a wiring diagram for the amp - looks like it confirms there are 3 12v feeds, yet mine only seems to be showing 1, which sort of points to a blown fuse. The diagram refers to a 30A fuse (though putting one in the previously empty fuse location listed for the amp has made no difference, and it worked without one there before). Just need to find out where there might be an in-line fuse and see if replacing that, if it exists, makes things all musical again. Link to comment Share on other sites More sharing options...
AvantSE Posted April 17, 2009 Author Report Share Posted April 17, 2009 Wiring diagram attached. Amplifier_1[1].pdf Link to comment Share on other sites More sharing options...
shark_90 Posted April 17, 2009 Report Share Posted April 17, 2009 Have you tried removing the kick panel under the dash on the drivers side? There tends to be some relays and big fuses under there, so it could be worth a look. Link to comment Share on other sites More sharing options...
AvantSE Posted April 17, 2009 Author Report Share Posted April 17, 2009 Will make that my starting point tomorrow, cheers. If I can get this sorted I might celebrate with a sat-nav install Link to comment Share on other sites More sharing options...
AvantSE Posted April 18, 2009 Author Report Share Posted April 18, 2009 Bugger... ELSAWIN hasn't shed any light on the matter so I suppose tomorrow it's a case of trying to trace the +ve wires back towards the fusebox and see if there are any issues en route Link to comment Share on other sites More sharing options...
AvantSE Posted April 18, 2009 Author Report Share Posted April 18, 2009 (edited) FIXED!! After hours of studying Elsawin, and 3 hours of removing acres of crappy black plastic trim from the interior of the car, I came to the conclusion that there was no in-line fuse and that the thing was just "fecked". So in the best possible tradition, and with the aid of some red wire, a fuse holder, and the dreaded Scotchlok connectors, I temporarily bodged a live feed from the back of the radio to the amp, joined the 3 lives together, and finally there was sound - 3 weeks to the day that the sodding thing went Pete Tong. Bloody marvellous. Now all I have to do is get the wiring properly joined in to the back of the multiplug, and the job is done - no thanks to VW, who are the dealership equivalent of that **** Anthea Turner - pleasant enough to look at, but feck all use. Edited April 18, 2009 by AvantSE TYPO Link to comment Share on other sites More sharing options...
shark_90 Posted April 18, 2009 Report Share Posted April 18, 2009 Ah ha! So what on earth has gone wrong in the wiring I wonder?? I'd take it back to the dealer if I were you and stick two fingers up at them. Link to comment Share on other sites More sharing options...
AvantSE Posted April 18, 2009 Author Report Share Posted April 18, 2009 Should get chance to take it back in next week and hopefully get the diagnostic fee back. Bunch of tossers ! Link to comment Share on other sites More sharing options...
Muzzty Posted June 17, 2010 Report Share Posted June 17, 2010 Hello i have the same problems with my passat but can you tell which connection you bypass behind the radio unit and which connector on the amp? Or just give more details for how to make it work !! Thanks you for you long research and yes VW dealer is big crap!! Thanks to you!! Link to comment Share on other sites More sharing options...
tjsuszka Posted September 3, 2010 Report Share Posted September 3, 2010 I have the same problem. I have tried several amps and refused to pay $900 to the dealer to fix it. I pulled the stereo head unit out and I have an amp in place and plugged in. It powers on and the display works - No sound... I see the thick red wire and the thin red wire - What is the other hot wire that I need to tie into? Please help....!!! Thanks Link to comment Share on other sites More sharing options...
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