No AM radio signal on two aftermarket HUs?

[atebit]

I've tried two different model Alpine HUs in my 07 sedan, and have noticed in both cases that AM radio reception is pretty much non-existent. FM radio comes in strong/fine, so I don't think it's a case of a bad windshield antenna connection to the radio.

I originally had the "integrated" AM/FM/CD stereo in the car. I'm almost starting to wonder if the factory radio had a built-in AM loop antenna or something like that, instead of it using the windshield antenna? The only other thing I can think of is maybe there's a separate feed for the AM antenna on the wiring harness that I wasn't aware of.

Not having AM isn't a huge deal...99.995% of the time I'm listening to either XM or the iPod, but in my area there are some decent AM news stations that I listen to every once and a while. Has anyone else had an issue with AM (or even tried to listen to AM) after replacing their stock HU?

[enkid]

The antenna is in the rear glass. It is a powered antenna, and there is fair FM reception when unpowered. It could be that the current capability of the Alpine power antenna wire is too low. You may wish to try connecting the Yaris power antenna lead (Socket A pin 8) to the accessory lead (Socket A pin 3) instead of to the alpine blue wire. If your AM reception comes back, you may either leave it as is, or have the alpine turn on a relay to connect battery power to the antenna.

[atebit]

Ah...I didn't realize it was a powered antenna. My strong guess is that the power lead for the antenna isn't connected at all. FM reception is pretty good, so that much certainly bodes well with your theory. I'll have to yank the HU & check out the wiring...sounds like an easy fix.

Thanks for the info...I would have never guessed it was a powered antenna!

[earljail]

Does anybody know if the hatchback(liftback) also has a powered antenna? I don't get any AM reception in my car with an aftermarket deck.
If it has a powered antenna, which coloured(colored) wire on the Scosche wiring adaptor do I connect the powered antenna wire from my deck to?

Thanks,

earljail

[redbluff]

Originally Posted by earljail

Does anybody know if the hatchback(liftback) also has a powered antenna? I don't get any AM reception in my car with an aftermarket deck.
If it has a powered antenna, which coloured(colored) wire on the Scosche wiring adaptor do I connect the powered antenna wire from my deck to?

Thanks,

earljail

Same issue for me. Very poor AM recepton on the hatch back and not real good FM. Using an aftermarket radio. Called while it was under warranty and had them send me a new one. Put it in and does the exact same thing.

The hatch antenna is powered. How do we all know if we connected the wires correctly for the amplifier on the antenna to work?

[jbll]

I have the exact issue with my HB and Alpine Head Unit with FM reception
didn't try AM...

What do the power antenna change to the FM reception?

And btw, my reception was VERY good with my Toyota Heand Unit...

I tought the power antenna cable was for the antennas which go up and go down all alone....

[redbluff]

Originally Posted by jbll

I have the exact issue with my HB and Alpine Head Unit with FM reception
didn't try AM...

What do the power antenna change to the FM reception?

And btw, my reception was VERY good with my Toyota Heand Unit...

I tought the power antenna cable was for the antennas which go up and go down all alone....

The antenna is amplified to boost the signal. I only guess that we dont have the non stock units connected up right.

[jbll]

Originally Posted by redbluff

The antenna is amplified to boost the signal. I only guess that we dont have the non stock units connected up right.

so, if i change the wire, I will get a better reception???

[atebit]

Yes, powering the in-glass antenna now provides me with AM reception (as opposed to no AM reception) & improved FM reception!

[barryware]

Does anybody know how much current the antenna amplifier draws? The wire for a power antenna (motorized) or an external amplifier (on/off) on my head unit states 300mV max.

I have AM reception but it sucks. I too have made the mistake of not supplying power to the antenna amplifier.

[enkid]

I think the scoche adapter power antenna lead is blue....it might be blue with a white stripe

I *think* the antenna amplifier draws about an amp, but I'm not sure. I didn't measure it.

I do know that Yaris sedan's glass antenna is one of the best in the industry, beating antennas in cars most of us could only dream of owning...

[barryware]

Originally Posted by enkid

I *think* the antenna amplifier draws about an amp, but I'm not sure. I didn't measure it.

I just connected the amplifier lead to the accessory power wire. Done! perfect!

Reception is great now.

[paultyler_82]

Well at least Toyota doesn't use something like Nissan's Diversity Antenna... I have a rear-window printed antenna AND a power post type antenna, apparently the head unit decides which one is getting the best reception and switches, it's a real nice headache for aftermarket, as if my car's built in Bose Audio system's balanced-line signal output and odd impedences weren't bad enough.

[barryware]

Originally Posted by edwardthed

Barryware,

which wire did you connect to for the power antenna for the AM signal?

it has been so long, I don't remember. I use the complete service manual download from a link on this forum to find the wire that is in the radio harness plug.. Not sure, but I remember it as being blue.

Using the harness I bought for my head unit.. I connected the wire to power the rf amp to the switched 12v wire to the head unit.

So.. when ever I turn on the ignition, the rf amp powers up.

[auxmike]

Hmmm.. I'm experiencing the same misery with a 2013 Tc deck in my '08 hatch. No AM! as a talk radio fan I need it...
The 2013 deck needs an adapter cable to work on the '08 antenna plug. There is a powered wire for the antenna coming from the antenna adapter. So which color harness wire would I need to tap into to juice up my OEM antenna then? Can I just use a squeeze on wire tap instead of cutting?

[2005vitzRS]

I'm having similar problems and have written about it in this thread.

http://www.yarisworld.com/forums/showthread.php?t=46256

If anybody has a solution please let me know.

Cheers

[bobdawonderweasel]

Originally Posted by enkid

The antenna is in the rear glass. It is a powered antenna, and there is fair FM reception when unpowered. It could be that the current capability of the Alpine power antenna wire is too low. You may wish to try connecting the Yaris power antenna lead (Socket A pin 8) to the accessory lead (Socket A pin 3) instead of to the alpine blue wire. If your AM reception comes back, you may either leave it as is, or have the alpine turn on a relay to connect battery power to the antenna.

Confirmed on a 2007 Yaris sedan that the antenna amp needs power.

Scosche Radio Wiring Harness for 1987-Up Toyota Power/4 Speaker Connector
to
Kenwood Excelon KDC-X598 CD Receiver

I was having radio reception issues and connected the Blue wire on the Sc osche connector to the White/Blue wire on the Kenwood.

As soon as I powered on the unit my AM reception was working and the FM signal was strong.

The original radio was the factory integrate mode. It fried about a week ago. I did a bunch of Googling to see what I could replace it with. That's when I found this site. After using the Search function (yes I actually used it) I was able to install the new radio quite easily.

This last little glitch with the reception was the last outstanding issue.

I did solder all my wires and heat shrank them rather than use crimp connectors. I should note that I worked on avionics in the Air Force (B-52's and KC-135's) and have no fear of soldering and a working knowledge of wiring diagrams.

Thanks to everyone on Yaris World for your posts!!!

[tomkecil]

Originally Posted by barryware

it has been so long, I don't remember. I use the complete service manual download from a link on this forum to find the wire that is in the radio harness plug.. Not sure, but I remember it as being blue.

Using the harness I bought for my head unit.. I connected the wire to power the rf amp to the switched 12v wire to the head unit.

So.. when ever I turn on the ignition, the rf amp powers up.

I stumbled on this after Googling took me to lots of places. I had the same problem - AM dropping in and out and FM not nearly as good as it was with the original head unit. Both are now excellent on my 2007 Yaris sedan. If you're just finding this from a search here's the full picture:

removing old head unit
It took <1min to pop off the four fascia panels around the unit and undo the four screws that hold the deck in place. Easiest car I've installed on!

Mounting new head unit
I bought a single din Kenwood and a single din tray that's especially made for Toyotas and comes with the two black plastic 'filllers' that are the right size to fill the gap in the dash. The tray and fillers were $20 and fit perfectly - see picture

Connecting the cables
I bought a head unit wiring harness for later model Toyotas on eBay (~$12) and then soldered and heatshrinked the leads onto the other end of the harness that came with the Kenwood. As the harness was designed for ISO connections all the colours were a straight match to the Kenwood harness, so it was simple. I plugged it in and it all worked well except for the radio reception.

Fixing the radio reception
Thanks to the posts above and another search, I confirmed that the Yaris is fitted with a signal amplifier that sits in between the rear window antenna and the aerial lead in the dash. It received power from the old head unit via a lead in the factory harness that runs to the amp down the back of the car, but the new unit was not giving it power. The lead you're looking for is the all black one in the middle of the Yaris's blue plug. When you get 12V to it the reception returns to the great quality of the original head unit. The ISO Toyota harness pin that connects to that black lead is blue, and the Kenwood had a blue lead designed to switch those motorised antennas on when the head unit is on, so, connect blue to blue and the job's done.

I now have streaming bluetooth audio, good quality hands free phone calls (I mounted the supplied external microphone at the top of the trim on the driver's A pillar) and most importantly, a happy wife.