Newly installed aftermarket radio cannot receive AM channels - Toyota Nation Forum : Toyota Car and Truck Forums

Crankman · 05-21-2009, 12:44 PM

I recently installed an aftermarket CD/radio on my 2004 Corolla with the standard fitting and harness wiring. The radio is Pioneer 2100. Everything works fine except the AM radio signal is very very weak. Even for local channels I can barely hear the channels. I took the radio back to Bestbuy, they tested on their demo panel it worked fine. I put the original stock radio back and that worked fine too.

With the original stock radio, it does not have a dedicated ground wire, the ground wire is in the plug. Therefore I connect the Pioneer radio ground wire to the black ground wire from the harness. Antenna plug fits into the new radio very well. Anyone have any idea why the AM radio does receive good signal?

caddymac · 05-21-2009, 11:34 PM

Dd you hook up the power antenna lead on the harness?

Crankman · 05-21-2009, 11:49 PM

I don't have a power antenna, therefore I don't use that power antenna lead on the harness. I did plug in the original antenna which works perfectly on FM reception.

caddymac · 05-25-2009, 08:04 AM

Even though the antenna does not physically go up and down, it still needs power. Once again, hook up the power antenna lead on the harness.

Slaander · 05-25-2009, 11:20 AM

source from http://www.9th gencorolla.com/forum/...ad.php?t=28871

DIY - Making AM stations work with Aftermarket Headunits
PROBLEM: After installing an aftermarket headunit, AM station stops working
CAUSE: Signal Reception Amplifier is not getting any power.
(usually when you used a Scosche/Metra harness kit)
DIFFICULTY: Very Easy, even your grandpa could do it.

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Crankman · 05-25-2009, 11:55 PM

Thanks to all for the suggestions. Slaander, where is that white harness located? is it the one on the antenna wire? There is a blue Power Antenna wire on the Scosche harness, should I connect it to this wire? Or can I connect it to the red 12 volt ignition/shitched wire on the harness? Just curiosity, why the original stock radio doesn't need this wiring?

Crankman · 05-30-2009, 09:55 PM

Thanks a lot, gentlemen (I assume it's men's job :-) ) for all the help. I did it this afternoon. I inserted a lead to the harness and connect it to the ignition red wire, it works like a charm. I took pictures of the whole process just in case I may help someone. Thanks again.

caddymac · 06-01-2009, 10:03 PM

No problem - I've heard of this problem a lot on late model cars. There haven't been very many true power antennas installed on cars in nearly a decade, so people tend to think that the wire is just extra. Well, when the antenna is a short stubby bit or built into a window, there needs to be some sort of amplification to get decent signal strength.