Wierd Noise
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Wierd Noise
I have a 2002 F-150 that I purchased approx 1 month ago. Noticed today after I turned engine off I still had my headlamps on. While headlamps were on I could hear an electric motor hum similar to a fan running.This was with the ignition off and heater in off position, only headlamps on.
The sound seemed to come directly in front of me somewhere in the instrument cluster. I raised the hood to make sure it was not the ABS pump running as I have had a couple of ABS warning lights that come on unexpected and then reset when ignition is cycled (bought rear ABS sensor but not installed yet.). The pump was not running and the noise is confined to cab area. Anyone have an idea as to this noise that could be triggered by headlamp switch.I later started truck and shutoff without headlamps on and did not notice motor hum but I can get hum to start by turning on light switch and when turned back off noise stops!
The sound seemed to come directly in front of me somewhere in the instrument cluster. I raised the hood to make sure it was not the ABS pump running as I have had a couple of ABS warning lights that come on unexpected and then reset when ignition is cycled (bought rear ABS sensor but not installed yet.). The pump was not running and the noise is confined to cab area. Anyone have an idea as to this noise that could be triggered by headlamp switch.I later started truck and shutoff without headlamps on and did not notice motor hum but I can get hum to start by turning on light switch and when turned back off noise stops!
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From: Under the flightpath of old ORD 22R
Do you have the autolamp feature ?
Could be the autolamp module, or the relays for the headlamps.
These are under the oval on the dash.
One quick test, when you hear the buzzing, pull the autolamp fuse, this is fuse #29 in the cab fuse panel.
The engine compartment fuse panel, fuse #6 & fuse #3 are for the autolamp relays, as well as the main headlamp switch. These 3 fuses should cut all the power for the headlamps.
If this does not cure the buzzing sound, it could be the blower motor, so you can pull the blower motor fuse.
How did you confirm this is not the ABS pump making the noise ?
Could be the autolamp module, or the relays for the headlamps.
These are under the oval on the dash.
One quick test, when you hear the buzzing, pull the autolamp fuse, this is fuse #29 in the cab fuse panel.
The engine compartment fuse panel, fuse #6 & fuse #3 are for the autolamp relays, as well as the main headlamp switch. These 3 fuses should cut all the power for the headlamps.
If this does not cure the buzzing sound, it could be the blower motor, so you can pull the blower motor fuse.
How did you confirm this is not the ABS pump making the noise ?
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How did you confirm this is not the ABS pump making the noise ?
From what I have read the pump is located under the air filter box. I raised the hood and there is no noise inside the engine compartment while the fan hum is occuring. I am convinced the noise is inside the cab in the drivers side dash area, and no I do not have Auto Lamp headlamps. The noise is not what I would consider a buzz but the sound of an electric fan energized.
When ignition and headlamps are off there is no motor hum, wouldn't have noticed this sound if I had shut off headlamps before turning off engine. Other post on this forum point to the ABS module running even though the ignition is off and eventually drains battery.
From what I have read the pump is located under the air filter box. I raised the hood and there is no noise inside the engine compartment while the fan hum is occuring. I am convinced the noise is inside the cab in the drivers side dash area, and no I do not have Auto Lamp headlamps. The noise is not what I would consider a buzz but the sound of an electric fan energized.
When ignition and headlamps are off there is no motor hum, wouldn't have noticed this sound if I had shut off headlamps before turning off engine. Other post on this forum point to the ABS module running even though the ignition is off and eventually drains battery.
Last edited by 2002mjones; Jan 1, 2010 at 08:15 PM.