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:
> 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.?
>
>
>
>

--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.***.net/jerrypb/

 

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:
> 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.?
>
>
>
>

--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.***.net/jerrypb/

 

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:
> 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.?
>
>
>
>

--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.***.net/jerrypb/

 

Jeff Strickland did pass the time by typing:
> 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
<snippies>

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.

 

Jeff Strickland did pass the time by typing:
> 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
<snippies>

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.

 

Jeff Strickland did pass the time by typing:
> 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
<snippies>

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.

 

"DougW" <post.replies@invalid.address> wrote in message
news:mUArg.64563$9c6.56916@dukeread11...
> Jeff Strickland did pass the time by typing:
>> 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
> <snippies>
>
> 1) Bad ground on the radio chassis.
> 2) Antenna cable has come loose
> 3) noise cap/choke has gone south
>

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.




> 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.
>
>
>

 

"DougW" <post.replies@invalid.address> wrote in message
news:mUArg.64563$9c6.56916@dukeread11...
> Jeff Strickland did pass the time by typing:
>> 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
> <snippies>
>
> 1) Bad ground on the radio chassis.
> 2) Antenna cable has come loose
> 3) noise cap/choke has gone south
>

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.




> 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.
>
>
>

 

"DougW" <post.replies@invalid.address> wrote in message
news:mUArg.64563$9c6.56916@dukeread11...
> Jeff Strickland did pass the time by typing:
>> 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
> <snippies>
>
> 1) Bad ground on the radio chassis.
> 2) Antenna cable has come loose
> 3) noise cap/choke has gone south
>

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.




> 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.
>
>
>

 

Hi Jeff,
Some of the Broncos came with a Citizen Band radio, with a
combination AM, FM, CB, antenna that didn't work very well on any of the
frequencies. There should be just enough room to plug in a test antenna,
without pulling it.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/

Jeff Strickland wrote:
>
> 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.