No audio after head unit replacement

JonA

Member
Joined
Feb 25, 2015
Location
CT
TDI
2005.5 MK5 Jetta Pkg 1, 2002 MK4 VW Jetta TDI
Hi there guys, newbie here, just bought my first car last year, a 2000 VW Jetta TDI with 373k miles on it. I'm going to clean out my intake manifold soon, so I might be back if anything goes wrong there, but until then, I have a quick(?) question. I just installed an aftermarket head unit and I'm not getting any audio.

I connected the positive and negative battery wires, as well as the ignition switch wire first, to test the head unit would power on (success). I then tried playing some music on the head unit while connecting the positive and negative wires for one of the speakers. No audio. Checked volumes, all up, tried the same speaker in another channel on the head unit. No luck. Tried a different speaker in a few different channels on the head unit. Still nothing.

Am I missing something stupid here? I've tried to find something, and the only post out there that seemed related was this:

"Some of the early model MK4 VW's were Monsoon and had a factory amplifier which has to be turned on via a remote turn on lead in the harness (which is different from the 03+ VW's w/ Monsoon which were signal sensing - no remote turn on required).

From the facts I can assume 1. it has factory Monsoon, and 2. it's not being powered behind the radio."​

This sounds like my situation, but if it is, what do I need to do to fix it? Thanks in advance for any help, I've already found a ton of great resources on here!
 

JonA

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Joined
Feb 25, 2015
Location
CT
TDI
2005.5 MK5 Jetta Pkg 1, 2002 MK4 VW Jetta TDI
I should have mentioned that I'm not using a wiring harness adapter, hence the confusion. I've clipped the wires on the stock harness and using wire butts connected the wires that I listed (+/- battery as well as ignition). I haven't connected any of the speakers yet, only tested them by sticking them in the wiring butts without crimping.
 
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Seatman

Top Post Dawg
Joined
Apr 23, 2010
Location
Scotland
TDI
2007 Seat Alhambra 2L tdi
Google search for a pin out of the stereo wiring, should find one around somewhere, then you can connect up the remote wire for the amp from your new stereo to the pin for the amp.
 

JonA

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Joined
Feb 25, 2015
Location
CT
TDI
2005.5 MK5 Jetta Pkg 1, 2002 MK4 VW Jetta TDI
Thank you sooo much for your reply, I just want to clarify here, as I said I'm new to cars altogether and I want to learn as much as possible without messing up too much :) What you're saying is I need to search for the wire that goes to the amp so I can connect that to the HU, and that'll solve my problem?
 

Seatman

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Joined
Apr 23, 2010
Location
Scotland
TDI
2007 Seat Alhambra 2L tdi
If you have an amp then yes, if you search something like "Mk4 golf head unit pin out" or that you should find some info. I have links to some but we didn't get the monsoon stuff over here so I don't have that one.

But yeh, if you do have an amp then it most likely will need the wire connected to switch it on. Usually amps have a live to them permanently but don't actually switch on till they get the signal from the head unit.
 

JonA

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Joined
Feb 25, 2015
Location
CT
TDI
2005.5 MK5 Jetta Pkg 1, 2002 MK4 VW Jetta TDI
Awesome, thanks for the info. I've been assuming (possibly incorrectly?) that I have an amp as there is a black box with heat sink fins stuck to the roof on the right side of the trunk, and I'm guessing it's a Monsoon since the original HU is a Monsoon, but I guess I should probably take the metal cage that's holding it up off, which happens to be obscuring any information that might be there.

Edit: it's just occurred to my continuously slowing mind that I should be using the RCA pre-outs since I'll be taking advantage of the amp. So I'm going to check out what amp I've got back there, find out which pin I need, put that sucker together, and fire it up. Thanks million Seatman, I was getting really frustrated with lack of info.
 
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JonA

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Joined
Feb 25, 2015
Location
CT
TDI
2005.5 MK5 Jetta Pkg 1, 2002 MK4 VW Jetta TDI
Oh. Okay then. That makes my life a bit easier I guess. I came across that thread earlier but hadn't understood what was going on at the time (what a difference a few hours makes!), so just to be clear, I should be using the low level outputs (the RCA pre-outs) and it should be fine? This might explain why nothing was happening before when I was trying to use the high level outputs. I hope nothing was borked in the process!
 

Seatman

Top Post Dawg
Joined
Apr 23, 2010
Location
Scotland
TDI
2007 Seat Alhambra 2L tdi
It sounds like you just run the regular speakers wires to the amp, might need them all connected to make the amp switch on though.
 

JonA

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Joined
Feb 25, 2015
Location
CT
TDI
2005.5 MK5 Jetta Pkg 1, 2002 MK4 VW Jetta TDI
Excellent! I had a sneaking suspicion that was the case, but I didn't want to go through the trouble of doing all 8 wires in the cold, without much space and be wrong. That was it though, as soon as I wired up the third pair it started working! Let it be known to all penny pinchers after me that a harness is DEFINITELY worth the extra $5-$10 unless you're a masochistic fiddler :p

Now I'm wondering if there's any way to mod this HU so I can use the speed wire... that's the only thing I'll miss from the Monsoon, haha. Thanks so much Seatman!
 

Seatman

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Apr 23, 2010
Location
Scotland
TDI
2007 Seat Alhambra 2L tdi
You think you're masochistic, I retrofitted all the electric goodies in my car, had to figure out every wire to the ccm and chop them then solder them to the new plug. It was a mixture of yoga, masochism and technology haha
 

JonA

Member
Joined
Feb 25, 2015
Location
CT
TDI
2005.5 MK5 Jetta Pkg 1, 2002 MK4 VW Jetta TDI
Wow. Have you talked to your therapist? :rolleyes: Seriously though, there's something kind of meditative about doing something "the hard way," even if it is harder (though I'm not sure I'll ever reach the level of enlightenment you have!).
 
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