Elecrtical Noise !
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Elecrtical Noise !
When starting my 2005 Sport Trac, I hear a "pop" from , i think, the right speaker, & then I hear what sounds like an altenator "w
hine" for a few minutes.
the radio can be off or on...no difference. I get the same "pop" after stopping the engine & opening the door, which turns off the sound from the radio...Any guesses fellows ???.............."G"
( relay, ground, or what problem . I had a red warning light condition on a 97 T-bird than turned out to be a defective ground on some component...)
hine" for a few minutes.
the radio can be off or on...no difference. I get the same "pop" after stopping the engine & opening the door, which turns off the sound from the radio...Any guesses fellows ???.............."G"
( relay, ground, or what problem . I had a red warning light condition on a 97 T-bird than turned out to be a defective ground on some component...)
Logistics Pro
Joined: Jun 2009
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From: Cedar Rapids, IA
Assuming you have a stock audio system, do you know what "grade" of audio system your Sport Trac has? If it is an up-level system with an external amplifier it could be a bad ground of failed electrolytic capacitor. Since it will also make the noise when the audio system is off I am thinking it's probably not a problem in the head unit since I don't expect the output stages to be powered when the unit is turned off.
It would be beneficial to connect an oscilloscope to the right speaker wires to confirm the pop and whine are coming from the audio system. You could then trace it back to the amplifier, confirm if it's there, and if so, check the input to the amplifier to see whether or not its present on the input. I suspect though if you had access to a portable oscilloscope you would have already tried this.
-Rod
It would be beneficial to connect an oscilloscope to the right speaker wires to confirm the pop and whine are coming from the audio system. You could then trace it back to the amplifier, confirm if it's there, and if so, check the input to the amplifier to see whether or not its present on the input. I suspect though if you had access to a portable oscilloscope you would have already tried this.
-Rod
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Reply...
Shorod.....thanks so much for your reply & trouble shooting instructions. I believe I have the upgraded audio system, as I have the 6 CD player. I am thinking I may disconnect the amp. inputs & see if it goes away. I think the amp. is behind the rear L.H. seat behind the panel ?. There is an electrical unit there , I don't have a Dealer Manual.....look like an amp. I could also just run an external ground wire from the box to sheet metal, just to test this theory.....internal amp part failures are looking like big $$$$....."G"
Logistics Pro
Joined: Jun 2009
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From: Cedar Rapids, IA
I'm not sure where the amp is on in the Sport Trac and my newest service manual is for the 2002 model year. I could check that for the location of the amp that year as it may be the same as your 2005.
-Rod
-Rod
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Update
Shorod... thanks again. The Elect. unit behind the rear seat on the left turned out to be an Amp. for a speaker looking like a "sub woofer". Disconnecting the input cable made no difference to my problem. Have to find other amp, etc. May need to pull the proper fuse & see if the power-off mode to speakers/amps. may help locate the problem. I just don't want this event to wipe out some other electrical equip.......
I don't know why Ford leaves the radio circuit "on" until you open the driver door........ "G" ( may have to find that relay, or it may be in the programming
)
I don't know why Ford leaves the radio circuit "on" until you open the driver door........ "G" ( may have to find that relay, or it may be in the programming
)
Logistics Pro
Joined: Jun 2009
Posts: 4,817
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From: Cedar Rapids, IA
Per the 2002 factory service manual, all levels of audio systems had the front and rear speakers powered by the radio directly. If you have the "High Series Console" the rear speakers were plumbed through the Rear Integrated Control Panel but still received their power from the radio rather than an external amplifier. There was an additional amplifier for the optional subwoofer only.
But I'm not sure if your 2005 is the same.
-Rod
But I'm not sure if your 2005 is the same.
-Rod
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Douglas Krysiak
Audio & Video Systems, Navigation, Satellite Radio & Mobile Electronics
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Oct 14, 2005 05:21 AM
