QuestionQUESTION: I have a 2001 Nissan Altima. I installed a Kenwood head unit and I love it but the FM reception is horrible. So I decided that I would purchase an after market antenna that mounts on the inside of the windshield. When this antenna is plugged in to the head unit, it does not even turn on. So i bough an adapter so both antennas can be connected and the reception was better but it still is not very good at all. I had someone tell me to get HD radio because my head unit is HD ready but i thought that you have to have good a good antenna established before you go HD. What could be the problem with my stock antenna since it did work excellent with the stock radio? What should I do, I miss my radio.
ANSWER: Hi Eric,
You have a couple of issues here.
First of all, your Altima uses an AM/FM antenna that's embedded into the rear window glass. There's also a factory antenna amplifier. When the new head unit was installed, I'm guessing that you didn't connect the wire that activates the amplifier.
The activation wire should be black with a red stripe, located in the larger of the two factory radio plugs. If you used an adapter harness, the black/red wire should line up with a blue wire in the adapter harness. In order to activate the factory antenna amp, you need to connect this factory activation wire to either the blue wire or the blue/white wire in the Kenwood deck's harness.
Some Kenwood decks harnesses include a blue and blue/white wire, but only the blue/white works--the blue wire isn't meant to be used. This is common among their entry-level head units. Your installation instructions should tell you whether the blue wire in your deck's harness is active; but if you're not sure, then you should use the blue/white wire to activate the factory antenna amplifier.
So, to sum up: make sure that the black/red wire in the factory radio plug, which lines up with a blue wire in an after-market adapter harness, is connected to the blue/white wire from your Kenwood head unit. This should improve your radio reception, and you can get rid of the stick-on antenna.
Now, the next issue: why doesn't the head unit turn on without the factory antenna connection?
My guess is that you were either testing the head unit while it was removed from the dash, or you're using a plastic mounting kit for the new radio. The factory radio doesn't use a ground wire in the stock radio plug; it's grounded through the metal mounting brackets. When you install a new head unit, you need to connect your deck's black ground wire directly to the metal in the dash structure. (There may be a black ground wire in your Nissan adapter harness, but don't use it--it typically doesn't have a matching wire in the stock plug). If your ground wire isn't connected, the head unit can still operate with the factory antenna plugged in: the antenna shield functions as a (poor) ground. However, your new antenna probably wasn't grounded to the vehicle's chassis, so it didn't work.
While the deck may work, using the factory antenna as a ground, this isn't an ideal situation; so you'll want to make sure you check the Kenwood deck's ground connection.
Hope this helps!
Brian
---------- FOLLOW-UP ----------
QUESTION: So I was looking at my wires on the adaptor and I do not have a black wire with a red stripe. I do have a black wire with a white stripe free but that's all. Now what should I look for ?
AnswerEric,
The black/red wire should be in the factory radio plug, not the adapter harness. The black/white wire in your adapter isn't required for anything in your car. Do you have a blue wire in the adapter? If so, when you connect the adapter to the factory plug, the blue wire in the adapter should be lined up with a black/red wire in the factory plug.
I listed the black/red wire color because some people don't use adapter harnesses when they install the deck. If you're using the harness, then the blue wire in the harness is the one you'd need to look for.
Brian
