I'm wondering if anyone knows what could cause the alarm whistle to go off when the key is switched in both the I and II positions. It's the alarm whistle noise but it's very faint and just noticed it the other day when I was checking fluid levels in a quiet environment. It's a 2006 l322 full size non-supercharged.
Low alarm whistle when key is in I and II positions
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Does it sound like the alarm whistle? For me it's my actual alarm but it's very faint. You have to be somewhere quiet to hear it. I wonder if it's always done that or if something is wrong.
I never really sit in the car with the ignition on but as I am now. It doesn’t sound like an alarm but a very low whistle. Almost like a morse code type of whistle. Hard to explain but it’s an extremely quiet high pitch. Here’s hoping a knowledgeable person can help
The very faint high pitched whistle from inside the truck is most likely coming from the air aspirator fan that is behind the small grille on the HVAC controller. The fan sucks cabin air into a duct past a thermister to sense the cabin air temperature. Thats how the AUTO temperature control on the HVAC system maintains the cabin temperature. Over time the fan and duct gets covered in dust, dog hair, human hair, and whatever else is floating around inside the cabin and all that gunk collects on the fan blades and around the fan bearing and you get that high pitched whistle or squeeling noise. You need to blow the duct out with some of that compressed air in a can that you use to clean computer keyboards, or a compressed air line set low enough (say 15 psi) that you don't spin the fan blades off the motor shaft.
Thanks Mark
I will try that out at the weekend. You obviously know your stuff. First day on here and potential for a fix. Thanks again
Hi Mark
Ok I’ve got a free day. Where is it situated. Being naive of course.
Right behind that little 1" square panel with the louvers on it, on the left side of the HVAC controller in the dash under the LH temperature control knob. #14 below
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Stick your ear down by it and see if you can hear a whine from it. The fan is behind that grill, and is an integral part of the temperature control module.
![290464]()
Sometimes you can get a whistle if one of the 7 dampers in the dash doesn't fully open or close. Make sure you run the HVAC controller thru all the different modes (defrost, upper dash, floor, recirc, outside air etc) to exercise all the doors to see if the whistling noise comes or goes in one or more of those modes.
Stick your ear down by it and see if you can hear a whine from it. The fan is behind that grill, and is an integral part of the temperature control module.
Sometimes you can get a whistle if one of the 7 dampers in the dash doesn't fully open or close. Make sure you run the HVAC controller thru all the different modes (defrost, upper dash, floor, recirc, outside air etc) to exercise all the doors to see if the whistling noise comes or goes in one or more of those modes.
Yes that’s what I mean. This whistling sound appears when I turn ignition into 1 or 2. The sound comes from the passenger footwell.
I bet its one of your HVAC blend doors being stuck or slow. Mine has a short, 1-2second whistle when I start mine, and its one of the doors not opening quick enough. Don't know if it does it if I just turn the key to position 2 but don't start it.
If I turn ignition to 1 or 2 with no ac on, in fact nothing running. All I can hear is this whistling constantly. I could sit quietly in the truck for an hour and it won’t stop. Sometimes a clicking sound too and this by just turning the key with no car functions on. Very odd.
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