I have a 98 a4 with a stock Bose system. I installed an aftermarket headunit (kenwood kdc-bt752hd) and ever since I installed it it has been crappy radio reception, except when I am standing still. The old radio worked perfectly so I think since it's an hd radio receiver the stock antenna might not be strong enough? If that actually is the problem how can I fix it? If not whats up?

Also, I want to install 1-2 subs in my trunk. I have the stock Bose system with the amp hanging under the rear deck on the drivers side, my question is can I plug the subs into that amp or would I need to buy another amp and add more wiring?

 

To answer your first question: do you have a powered antenna adapter? You'll need one (if you don't already have one) to get better reception:
Antenna Adapter Works with select 1994-up Volkswagen and Audi vehicles (Motorola male to OEM antenna female) at Crutchfield.com
I believe the stock head unit has this built-in, but aftermarket head units do not.

 

Yes, I ordered from crutchfield so I got all the adapters and everything with the radio, it's possible I just didn't connect the three wires correctly to power it. Ill take it back out and redo it

 

You will need to buy a separate amp for the subwoofers. You will also need an amplifier wiring kit which should include a set of RCA cables, remote wire and a ground wire. The RCA cables will plug into the back of your kenwood and be ran to the new amp, same with the remote wire. The ground wire will be hooked up to your amp and bolted to a good ground.

edit,

forgot the amp kit will come with a power wire as well, which will run from the amp to the battery.

I installed an aftermarket headunit in the same car you have and my radio works fine so I'm assuming you mis-wired something, mine came from crutchfield too so I believe we got all the same accessories for install.

 

Thanks for the info on the subs, As far as the headunit when I get some time ill tear it all back out and rewire the wire from the antenna adapter. One thing I though was weird was that It didn't need to be grounded (none of the adapters that is), I thought I would of had too, should it have been?

 

I bought this kit from this dealer on amazon And I do not get good radio reception either. I don't know if maybe I did not hook up a wire or something the antenna adapter has a wire but it did not make a difference if I gave it power or not