Car Stereos: AM Band Not Working, antenna amplifier, 2008 toyota corolla

Question
I replaced my factory radio with a Kenwood CD Receiver in my 2008 Toyota Corolla and the Kenwood would not receive AM stations.  So I decided to purchase a better quality radio. I just installed a new Pioneer FH-P8000BT and I can not receive AM stations on that radio. The Am Band works just fine with the factory radio installed. Any suggestions?

Thanks, Al  

Answer
Hi Al,

I suspect your Corolla is equipped with a factory antenna amplifier.  This is very common on newer Toyota vehicles with the AM/FM antenna embedded in the rear window glass.

When you install a new head unit, you need to activate the antenna amplifier.  This is done by powering a wire in the radio harness.

If you're using a wire harness adapter, there should be a blue wire.  This blue wire needs to be connected to the blue/white wire on the after-market head unit.

Here's what I think happened:  I suspect that when you used the Kenwood deck, you connected the blue adapter harness wire to the blue Kenwood wire.  Unfortunately, on some Kenwood models, the blue wire isn't functional--it's only included because the same harness is used for other models as well.  So your antenna amplifier wasn't activated when you installed the Kenwood deck.  Then you switched to the Pioneer deck, which has no blue wire at all.  In this case, I'm guessing you left the blue adapter harness wire disconnected.

Try connecting the blue wire in the adapter harness to the blue/white wire from your head unit.  This should activate the factory amplifier, and give you back your AM reception.

Hope this helps!

Brian