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OT --- Radio Static - AM Band, Engine OFF

I have static in my AM radio in the Bronco. When the key is set to ACC, the radio works fine, but as soon as I set the key to ON (but not START), the radio produces a loud hiss that drowns out the audio of the station I have selected. the radio works pretty well in ACC, it can get a wide range of stations, but when the key is set to ON, whichever station is dialed in at the time is overcome with hissing or static.

What sorts of circuits in my Bronco can produce noise in the radio?

Remember, the noise is not coming from the ignition circuit because it happens while the motor is not even running. In fact, the noise remains the same after the motor starts, and does not change with engine speed.

The hissing does not sound like it comes from a motor (fuel pump), but I suppose it could come from a circuit that has a motor (fuel delivery).

The power source for the radio is hot when the ignition is in ACC or ON, but in ACC there is no noise. This means that another circuit that is hot in ON, but not hot in ACC has to be the source of my trouble. It's times like this when I wish I had a Factory Shop Manual.

Jerry B.?

Reply to
Jeff Strickland
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My vote would be for the fuel pump. After that I would look to whatever computers the Bronco has running. The fuel pump is the most likely culprit.

The place to start is with your dealer. Most manufacturers have service bulletins and fixes for radio frequency interference (RFI.) A good place to get information is on the ARRL amateur radio site.

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Although this is aimedprimarily at 2-way communications equipment, much of the informationwould be applicable to the broadcast band. Dick

Reply to
Dick

Start pulling fuses (one at a time) and see which one makes a difference

Reply to
Stupendous Man

Reply to
RoyJ

Jeff, I'd suspect maybe the fuel pump. Can you pull the fuel pump fuse or at least unplug the fuel pump to see if that stops the noise? If it does, I'd power the AM radio from a different fuse or directly to the battery which may help.

Jerry

Jeff Strickland wrote:

Reply to
Jerry Bransford

Jeff Strickland did pass the time by typing:

1) Bad ground on the radio chassis. 2) Antenna cable has come loose 3) noise cap/choke has gone south

If you have a transistor radio :) see if it picks up any noise and use it like a little sniffer.

If all else fails you could simply go to radioshack and get a 12V auto power filter doodad. Coil and cap in a heat shrink package. Splice that into the radio power.

Reply to
DougW

All of these things would make the radio work poorly all of the time. The radio works without flaw when the ignition is set to ACC.

Reply to
Jeff Strickland

Reply to
L.W.(Bill) Hughes III

Jeff Strickland did pass the time by typing:

erm. no.

There is no external noise source in ACC. The OP's problem is in ON when items such as the pump are running. In that situation any bad ground or open circuit will allow noise in. And AM is nothing but suceptable to noise.

Reply to
DougW

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