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AM radio has lots of noise
Hello all
For the last year the AM radio on my 2000 323i has lot's of static noise. FM works perfectly fine.
In some areas in the city the AM channel works clear and in some areas it is unbearable so I can't hear a word.
What can be done to fix the AM channel receiver?
Last edited by Yober; 09-18-2017 at 08:43 PM.
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Clean the antenna contacts in the c-pillar, passenger side IIRC.
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Your car's antenna is embedded in the rear windshield. The signals (AM & FM) are amplified by an amp located in the "C" pillar on the right side of the car. Gently remove the reading light and you'll see a bolt (10mm if memory serves me). Remove the bolt and VERY gently pull the cover off. It's held in place by the bolt and 3 (?) plastic clips. The cover is old and will be brittle so be gentle. The amp is bolted to the "C" of the body. Remove the RF input connectors and clean both sides with alcohol. Reinstall and make sure the connectors are tight. Try the AM radio to make sure you've fixed the problem before you reinstall the cover. You many need a new amp. Make sure the new amp has the same RF frequency (315mhz) on the label as BMW changed the amp in MY2003.
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My 325xi wagon has the antenna inside the left-rear wagon window....and has very poor reception in FM radio and I've not tried AM radio but can imagine a similar for poor radio reception. The rear-roof mounted aerial on BMW cars is NOT there for you're fm-am radio but only there for cellular phone....did you know?
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someone still listens to AM radio?
Charlie
Your mission, should you decide to accept it, is to add value to these threads, either by pictures or by descriptions, so the next person with the same or similar problem stands on your shoulders.
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Check the antenna cable connection on the back of the radio in the dashboard and any wire connections that might have been added to the radio.
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yes, local newsOriginally Posted by Honolulu
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Hi MarcoZandrini,
I did all as per your instructions. All 3 connectors to the amplifier were very clean, but i brushed it and cleaned with the alcohol. Connected all back, but no any change.
Then I disconnected one by one the 3 connectors in order to identify which one is for AM, but to my surprise there was no any difference for the reception on both FM and AM. When I disconnected completely the amplifier and turned On the radio , the FM and AM were working as usual (i.e. FM reception was OK, AM reception was with the static noise). Feels like the amplifier didn't play any role for the radio reception.
One thing that i noticed : at the spots where the wires are connected/soldered to the rear windshield there is a white powdery substance which I suspect is the corrosion developed from the moisture. I tried to scrape as much as possible, but there is a narrow access under the metal plates that are soldered to the glass. I'm thinking to use vinegar and with the Qtips to melt the corrosion under those connector plates at rear windshield.
As for the amplifier, it looks perfectly fine. However I am puzzled, i.e. when I removed the amplifier and tried the radio without it, the radio worked as usual as if there is no change.
Last edited by Yober; 09-25-2017 at 06:10 PM.
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I’m betting the RF amp is the culprit. Or, it’s not getting power from the head unit. Pull the connector from from the RF amp. Make sure one of the pins is grounded and another pin has 12VDC when the head unit is on. The connector you need to che k is the one on the opposite side of the RF connectors. See the diagram in the link.
http://www.realoem.com/bmw/enUS/show...diagId=65_0481
Last edited by MarcoZandrini; 09-26-2017 at 09:27 AM.
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OK thanks, I will try to test this module.
By the way I phoned dealer for a quote for this module, and they told me that it's called Antenna Module (not RF Amplifier). On the diagram which you provided this module shown as part #1 called TRAP CIRCUIT.
I wonder if I need to find and check the actual Amplifier as well ?
Also what about my intent to clean the corrosion residue at the windshield, i.e. is it worth to clean?
Last edited by Yober; 09-26-2017 at 03:10 PM.
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Living in Los Angeles, the AM tells you the traffic and brush fire locations.
Could be important. My Z-3 has the same problem.
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issue is still not resolved.
i didn't get a response to my question in the post #10 above.
Last edited by Yober; 04-07-2018 at 12:46 AM.
Member
Ok, let’s pull the head unit and check the 2 RF connectors at the rear. I’m betting they’re on tightly, but check them anyway. Did the AM static happen all at once or did it a gradually degrade? As mentioned above, check the rear windshield connections for a bad connection. Also, the RF amp could be bad. You could just get a used one from a local auto recycling place. Be aware that BMW changed the design of the E46 RF amp for model year 2003. The one you need must have “315MHZ” on the label. The RF amp with “4xxMHZ” won’t eotk as it has a single RF output!
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