New 2003 TT Coupe owner. I have read all the threads on several forums about installing aftermarket stereo and there is some great info. but have to say I'm totally confused and have never installed a stereo before. It seems really simple but when you do it, it appears confusing. I apologize if this rehashing but I'm really confused and can't get any sound out of my new head unit.

Can someone confirm, help with the following

- I am assuming a have a factory amp because it starts up and says bose on the stereo - is that confirmation that I have a factory amp? I have the original owners manual and stereo manual and it mentions nothing about an amp.

The following assumes I do have an amp.

- i hooked up a Metra wiring harness - this one.
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It looks like this:









So my question is what do I need to wire to the aftermarket unit?

It looks like i get power and ground from the black harness and speaker outs from the red harness. Do I just need to plug in the RCA connectors to the aftermarket unit and that should give me sound? What about all the other wires on the red harness that aren't pinned? That's where I'm confused.

I got power to the deck and plugged in the RCA connectors to the new head unit and don't get any sound - should I have sound at that point? What else do I need to do to get any sound?

I seen threads saying that's all I need is the correct harness, while other posts say need to splice into original wiring harness plus the metra wiring harness is not fully pinned so it seems some of the original wires are not getting connected. Head is spinning! I know this is suppose to be relatively simple.

Hope someone can explain/clarify things. Much appreciated.

 

I know this is a month late, so hopefully you found some success.

If not... first -- you have Bose, so you have a factory amp. You can just plug in the RCA cables to the front and rear connections on your new head unit. The Metra harness comes with a pamphlet that explains what each color connects to, and you match those labels up with the harness that came with the head unit. You're mostly concerned with power, accessory, and antenna power. If you don't have an antenna power amplifier, you'll need one if you want to listen to FM radio. The other kicker is that you're going to need to run a wire for your switched accessory power, as one isn't really run for the TT, the stock radio uses canbus to determine accessory state. There are threads all over for that, but what I ended up doing was tapping under dash power. If you look under your driver's side dash, you'll see a block of numbered terminals. On the far left is 75x yellow. Running a wire from that up to where your stereo is will give you success.