2006 hyundai sonata with pioneer DEH-P6200BT gives very weak AM reception. Only receiving two stations.FM is fine.

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If you can get access to under the antenna check that the wiring plug is fully inserted.

do you need the wiring for the deck or for the car(or both)

Sounds like the dealer may be correct to me, but make them guarantee the job.

It sounds like you are just in a weak reception area. If you feel this is not the case first try replacing the entire antenna assembly, it would be the primary cause of this type of problem.

I really hate to say it, but AM reception has been a problem for over 50 years....that's why FM was invented....

Anyway, if the FM stations are coming in and none of the AM stations are working, the problem has to be inside the radio unit itself.

Check your aerial/antenna, it cannot find any station because it is not getting any reception.

AM is reflective, FM is not. Best reception is always FM because of this reason. Reflective AM bounces off everything - buildings, trucks, houses, power poles, etc and cause 'shadow' RF which confuses the the radio's AM tuner. However, if this condition exists ALL the time (whether you driving or in your garage), then the problem is either in the audio unit itself or in the rear window antenna (or connection to it). Left "C" pillar cover removed, you'll see the physical connections to the window antenna (it's also the rear defroster heating elements).

check radio antenna. could be loose connection or antenna missing or broken.

try the brakelight switch, it is right near the pedal above the footpad