electrical or alternator buzz noise
electrical or alternator buzz noise Sorry it's long, but I am really baffled and this place always seems to have the answer.
Car is a 2007 Grand Prix GXP LS4 stock engine/intake with 102000miles. There is an almost to always constant whine/buzz noise coming from the dashboard/fire wall area. Can't really tell a side. Started in December 2014. The noise is similar to a LS1 F-body AIR pump. The noise is always present at cold starts and generally continuously there but does get a little bit quieter once warm. For certain not the HVAC air path doors, blower motor, speakers/monsoon. I cannot find any rubs in the engine area or dashboard. I have seen the post about clunks, buzz from the ventilation ducting motors and really do not think this is it; can hear the motors operate at a different pitch and assume if one was bad that turning the ventilation system off would result in the command to move stopping as well as the noise. Also noise stops at car off - not a retained power item. Yesterday I rolled the windows down for the first time in a while and the noise decreased. So moving the windows results in a slight decrease in the volume of the noise especially when the windows are at the end of travel but switch is still pressed. Pressing two switches with both windows at end of travel results in a noticed decrease in volume and a slight decrease in hum pitch. Independent of any particular window. No change with another load like seat heaters/ high beams. Windows and motors appear to function fine both smooth and at roughly the speed when car was purchased in 2009. I am beginning to suspect the alternator (not pulley? - cannot really hear in the engine compartment, only in the car).
Is this possible as I've never heard an alternator make this noise before?
Anything else to look for or check?
Any electrical control of the alternator that could fail? I read through the description of how the charging system is controlled and am still dumbfounded by how something so simple can be engineered into something that messed up.
I did a quick check of battery/alternator wires and all look good. I will do a more extensive check on the resistance and solid connections for all the heavy wires this weekend. Original battery was replaced in Sept 2014 after a DIC charging system failure message. Been watching voltage more closely and will jump to 15+/- 0.4V right after startup then stay in the mid 14's or maybe fall to mid 13's during long 90min plus drives.
Thoughts?
Car is a 2007 Grand Prix GXP LS4 stock engine/intake with 102000miles. There is an almost to always constant whine/buzz noise coming from the dashboard/fire wall area. Can't really tell a side. Started in December 2014. The noise is similar to a LS1 F-body AIR pump. The noise is always present at cold starts and generally continuously there but does get a little bit quieter once warm. For certain not the HVAC air path doors, blower motor, speakers/monsoon. I cannot find any rubs in the engine area or dashboard. I have seen the post about clunks, buzz from the ventilation ducting motors and really do not think this is it; can hear the motors operate at a different pitch and assume if one was bad that turning the ventilation system off would result in the command to move stopping as well as the noise. Also noise stops at car off - not a retained power item. Yesterday I rolled the windows down for the first time in a while and the noise decreased. So moving the windows results in a slight decrease in the volume of the noise especially when the windows are at the end of travel but switch is still pressed. Pressing two switches with both windows at end of travel results in a noticed decrease in volume and a slight decrease in hum pitch. Independent of any particular window. No change with another load like seat heaters/ high beams. Windows and motors appear to function fine both smooth and at roughly the speed when car was purchased in 2009. I am beginning to suspect the alternator (not pulley? - cannot really hear in the engine compartment, only in the car).
Is this possible as I've never heard an alternator make this noise before?
Anything else to look for or check?
Any electrical control of the alternator that could fail? I read through the description of how the charging system is controlled and am still dumbfounded by how something so simple can be engineered into something that messed up.
I did a quick check of battery/alternator wires and all look good. I will do a more extensive check on the resistance and solid connections for all the heavy wires this weekend. Original battery was replaced in Sept 2014 after a DIC charging system failure message. Been watching voltage more closely and will jump to 15+/- 0.4V right after startup then stay in the mid 14's or maybe fall to mid 13's during long 90min plus drives.
Thoughts?
