C8 high pitched buzzing sound
Thread Starter
Intermediate
Joined: Nov 2007
Posts: 29
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C8 high pitched buzzing sound
I have a 22 C8 coup, Z51, mag ride, 1700/miles. The car had the "lights always on" problem. The dealer reprogrammed two modules, which fixed the problem. However, when I pulled into the garage, and turned it off, I heard a high pitched buzzing sound coming from under the frunk. New sound. The sound lasted about 30 seconds to a minute. Pulled the frunk covers, started the car, shut it off, and the buzz started again. traced it (I think) to some module attached to what appears to be something to do with A/C. Unfortunately I am unable to identify car parts any more, so really not sure. Was wondering if anyone else has experienced this sound?
Race Director
Joined: Mar 2007
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My front lift will sometimes make a buzzing sound and sometimes not. I have it set to lift in my driveway. But, after the car is shut off, it lowers, and sometimes buzzes. After the car is off, the lift will immediately start to lower, unless a door is opened. Even so, it will (according to the manual) only temporarily stop lowering. Then it will lower anyway.
My car also makes other more subtle clicking and soft humming noises from time to time after turned off, or after first turned on. I ignore them
My car also makes other more subtle clicking and soft humming noises from time to time after turned off, or after first turned on. I ignore them
Thread Starter
Intermediate
Joined: Nov 2007
Posts: 29
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Thanks. Rarely use the front lift. So, I don't think it's that. But, you make a good point, probably not anything I need to worry about. As my doctor always says "Let's just keep an eye on that". Thanks for your input.
Race Director
Joined: Mar 2010
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I have a 22 C8 coup, Z51, mag ride, 1700/miles. The car had the "lights always on" problem. The dealer reprogrammed two modules, which fixed the problem. However, when I pulled into the garage, and turned it off, I heard a high pitched buzzing sound coming from under the frunk. New sound. The sound lasted about 30 seconds to a minute. Pulled the frunk covers, started the car, shut it off, and the buzz started again. traced it (I think) to some module attached to what appears to be something to do with A/C. Unfortunately I am unable to identify car parts any more, so really not sure. Was wondering if anyone else has experienced this sound?
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Pro
Joined: Jul 2002
Posts: 595
Likes: 90
From: Lisbon WI
I am betting whatever it is might be the same.
Intermediate
Joined: Jun 2022
Posts: 33
Likes: 23
The headlights have a built-in fan and can run after shutdown, similar to the radiator fans. Interesting enough, I noticed the same thing from my passenger side light. Later I discovered that the high beam on that same light did not work. Dealer changed the light and I have not heard the fan run since then. I would check my high beams just to make sure it is not a related issue. But the fans running is normal, especially after night driving.
I also have a 2022.
I also have a 2022.
Race Director
Joined: Mar 2007
Posts: 11,461
Likes: 8,632
The headlights have a built-in fan and can run after shutdown, similar to the radiator fans. Interesting enough, I noticed the same thing from my passenger side light. Later I discovered that the high beam on that same light did not work. Dealer changed the light and I have not heard the fan run since then. I would check my high beams just to make sure it is not a related issue. But the fans running is normal, especially after night driving.
I also have a 2022.
I also have a 2022.
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Racer
Joined: Nov 2021
Posts: 482
Likes: 428
From: NE Ohio
We have a Honda CR-V that occasionally makes a buzzing sound with the engine off. Had me concerned until I read this from a service bulletin:
Noise from Under Vehicle: This noise is caused by the vacuum pump inside the fuel evaporation leakage check module (ELCM). Depending on conditions, the pump will come on for about 15 minutes about 5 to 10 hours after engine shutoff.
Made perfect sense after I read it! I have no idea whether the C8 has similar equipment, but thought I'd share.
Noise from Under Vehicle: This noise is caused by the vacuum pump inside the fuel evaporation leakage check module (ELCM). Depending on conditions, the pump will come on for about 15 minutes about 5 to 10 hours after engine shutoff.
Made perfect sense after I read it! I have no idea whether the C8 has similar equipment, but thought I'd share.
Intermediate
Joined: Jun 2022
Posts: 33
Likes: 23
We have a Honda CR-V that occasionally makes a buzzing sound with the engine off. Had me concerned until I read this from a service bulletin:
Noise from Under Vehicle: This noise is caused by the vacuum pump inside the fuel evaporation leakage check module (ELCM). Depending on conditions, the pump will come on for about 15 minutes about 5 to 10 hours after engine shutoff.
Made perfect sense after I read it! I have no idea whether the C8 has similar equipment, but thought I'd share.
Noise from Under Vehicle: This noise is caused by the vacuum pump inside the fuel evaporation leakage check module (ELCM). Depending on conditions, the pump will come on for about 15 minutes about 5 to 10 hours after engine shutoff.
Made perfect sense after I read it! I have no idea whether the C8 has similar equipment, but thought I'd share.
Race Director
Joined: Mar 2007
Posts: 11,461
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Yes, my MBZ does that, but it is from the bottom of the car... this is from the headlight, you can put your ear by it and it come from right behind the light... The fans are designed to keep the lights cool and extend the life of the headlight. At the dealer (non-warranty) they are about $1900 each.
