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I have a 2000 Crown Vic I just bought a couple weeks ago. It's the LX package, and still in great shape.

One thing that's come up in the two weeks I've been driving it: Every now and then, seemingly at random times, I get a very high-pitched whine coming from what seems like just under the dash or maybe from behind the radio/heater controls.

It's not the radio - it happens whether the radio is on or off. It definitely has something to do with the heater controls, though, because if, for example, the heat or fan is off, turning it on to vent/floor/defrost will kill the noise. If the heat or fan is on when it starts, switching it off has the same effect. I've yet to notice it happen when the A/C is on.

It's totally random, and I can't figure out if there's a catalyst or not. It seems that it might happen one time one day for maybe 5 or 10 seconds, and then not happen for three days. Then it will come and go steadily over the course of a day or two for as little as 5 or 10 seconds but sometimes lasts a minute or two, then not happen again for a week.

The guy who owned the car before me said he though it was the flapper in the air ducts that switches the air from vent to floor to defrost had a bad seal or something, but it doesn't sound like that kind of noise to me - vehicle speed plays no part in the sound of the noise, and if it were leaking air, the inrush or the fan speed would play a definite part in how it sounds.

To me it sounds more like an electronic noise, maybe like the seat-belt dinger or lights on/car off bell would sound if it were shorting out against something intermittently. But, again, bumps in the road or taking corners isn't what causes it.

I'm just wondering if anybody's had a similar experience or knows someone who has, or maybe saw a bulletin posted somewhere that describes the problem and a solution. I don't want to kill a Saturday ripping my dash apart to go on a wild goose chase, or god forbid, pay a mechanic umpteen hundred dollars to do it for me.
 

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I haven't heard anything like that. Could it be transfering from under the hood? Maybe the drive belt or pulleys? Maybe the A/c heater blower motor bearing going out.
 

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I haven't heard anything like that. Could it be transfering from under the hood? Maybe the drive belt or pulleys? Maybe the A/c heater blower motor bearing going out.
I suppose it could be coming from under the hood. I haven't looked around under there for a possible source, so I'll look into that today.

I don't think it's a bearing in the fan, though. Like I said before, it happens when the heat or A/C is turned off, too. In fact, most of the time it happens is when the heat controls are turned right off - and I haven't heard it happen when A/C is on at all.

Maybe I can make a small recording or something...
 

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Maybe I can make a small recording or something...
That might help. I'd say to check under the hood. The drivebelt or one of the pulleys could be causing the noise. The electric cooling fan for the engine could also.
 

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That might help. I'd say to check under the hood. The drivebelt or one of the pulleys could be causing the noise. The electric cooling fan for the engine could also.
I will admit that since I don't have a clue as to what it is, anything's possible. However, I've heard my fair share of pulley noises and I don't think it's a belt or a pulley. The engine fan can be heard kicking on and off when it does, and the noise occurs whether the fan is on or not.

Plus, like I said, fumbling with the heater controls can stop it from happening (sometimes for a short time, sometimes for a day or more). I would think a mechanical problem would be both more constant and more consistent . It has more of an electronic sound to it than a mechanical sound, if that makes sense.
 

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Plus, like I said, fumbling with the heater controls can stop it from happening (sometimes for a short time, sometimes for a day or more). I would think a mechanical problem would be both more constant and more consistent . It has more of an electronic sound to it than a mechanical sound, if that makes sense.
The change with the controls can easily be cooincidental. A bearing in the pulleys often come and go then finally stay more constant.
 

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it's more likely a vacuum hissing that you're hearing from the climate zone switch on the heater panel. I'd bet you still hear the hissing for a little bit after they car is keyed off. That switch is operated by vacuum and when the switch goes bad, you actually hear a vacuum leak. I work for a taxi company that primarily runs crown vics and it's been a fairly common occurance. Hope that helps
 

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I haven't heard anything like that. Could it be transfering from under the hood? Maybe the drive belt or pulleys? Maybe the A/c heater blower motor bearing going out.
I'm having the same problem and it's coming from inside the car, and I currently don't have speakers in the front so it cant be the stereo
 

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it's more likely a vacuum hissing that you're hearing from the climate zone switch on the heater panel. I'd bet you still hear the hissing for a little bit after they car is keyed off. That switch is operated by vacuum and when the switch goes bad, you actually hear a vacuum leak. I work for a taxi company that primarily runs crown vics and it's been a fairly common occurance. Hope that helps
How do I fix it boss
 

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The only thing behind the radio that comes to mind is the blend door actuator for the heater\AC vents, but I don't know how it would make a high pitch noise unless the actuator arm is binding up on something - very unlikely I would think.

The gears inside the actuator are known to strip and make a constant clicking sound as the actuator motor tries repeatedly to regulate the air flow. While parked, turn the ignition on but do not start the engine. Adjust all heat\AC controls and listen for the noise. If you can still hear the noise the odds of it being in the engine compartment are somewhere between highly unlikely to almost impossible.
 

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How do I fix it boss
Vac leaks can make different noises , high pitch whistle is quite common dependant on where leak is ..
Check this from someone who works on a fleet of 800 Crown Vics and see this regularly.

Start under the hood. There's a vacuum line that runs through the firewall at or very near the heater hoses. That vacuum line is connected to manifold vacuum at one end and a "T" at the other with a Check valve and a vacuum reservoir. The check valve and reservoir keep vacuum on the Climate Control system when pulling a long grade or at an extended WOT. The default is Defrost if the vacuum fails. Vacuum leak at reservoir, failed check valve, vacuum leak at control head. Start simple under the hood - at the source and work your way back.
 
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