Loud sound from rear of vehicle when reversing

[muayad925]

Hello, I am having an issue with my car when it comes to reverersing. When i set the car into reverse a loud sound comes from inside the interior of the rear of the car, under the carpet where the rear speakers are. It sounds like something like a stuck A/c actuator but much louder. The sound lasts for 30 seconds then stops, and it only does it the first time I put the car in reverse. I can put my car reverse as much times after, and it wont make the sound unless I restart the car. No problems with back up camera, reverse lights or the reverse beeping noise. I dont know what could possibly cause it.

2012 M35h, 130k miles

[Ilya]

Hi there.

Do you have a video or something that maybe we can view?

[Debonair]

muayad925- I believe the area you are describing houses some of the hybrid equipment. My guess is that it is related to this since the gas M/Q70's don't have any equipment in this area that I think could make this noise. Maybe a relay or motor of some sort.

Video from inside the car and the trunk took while someone puts the vehicle into reverse, as Ilya suggested, will help.

[muayad925]

https://youtu.be/wUvtTWjYszk

Ill record a better video if needed. And what part of the hybrid system would cause this to happen only in reverse? The whole battery is under that area.

[Debonair]

Whoa! That's crazy loud. I'll look over the wiring and diag charts tomorrow and see if anything jumps out.

[muayad925]

Discovered that the rear sun shade was the source of the problem, well i think it is. If i bring down the sunshade i could replicate the sound. Just confused with what it has to do when reversing??

https://youtu.be/frQ6pTxe3ws

[Ilya]

Discovered that the rear sun shade was the source of the problem, well i think it is. If i bring down the sunshade i could replicate the sound. Just confused with what it has to do when reversing??

https://youtu.be/frQ6pTxe3ws

Is it up when you get in the car? If it's up, then I think by default the system puts it down so you can see out the rear window still when backing up.

[knelson]

Discovered that the rear sun shade was the source of the problem, well i think it is. If i bring down the sunshade i could replicate the sound. Just confused with what it has to do when reversing??

https://youtu.be/frQ6pTxe3ws

Is it up when you get in the car? If it's up, then I think by default the system puts it down so you can see out the rear window still when backing up.

I'm guessing when putting into Reverse, something is telling the rear shade motor to run regardless if it's up or down. It must think it's up all the time, and trying to lower it. And the result has stripped the gears maybe. This is a slightly educated guess. But boy that noise is loud and must be annoying. Let us know what you find out.

[muayad925]

Ive always had it down but i guess the car still tries to bring it down when i put it in reverse. I guess its the motor going out because when its all the way up it gets stuck and i have to manually push it down. Do you guys know where the fuse is located? I dont really care for it and would rather disable it than fix it. Ive checked all 3 fuse boxes amd coudnt pinppint which one controls it.

[EdBwoy]

Prior postings indicated that these cars' sunshades are supposed to lower in reverse.
rear-power-sunshade-when-in-drive-t608637.html


My guess is that your limit switch(es) on the sunshade are goofy and the car doesn't get the signal that the shade is fully lowered.
I can't remember if the shade usually got a dedicated fuse. If it does, it will be something like "PWR Screen" or "PWR Shade" or "Rear Screen". If it comes to the worst, I'd just disconnect the plug that powers it; again without going into the FSM I'll guess it's behind the rear seat back or under the rear parcel shelf.

Check the FSM, linked in my signature, to see if you get some more definite direction to disable it.

Edit:
The section is INT, starting at pg 10.
Fuse #3 which is a 10 Amp fuse seems most relevant, followed by #4, another 10A fuse.

[Debonair]

Glad you found the issue. Hopefully you don't have to sell a kidney to correct it.

[armybrat]

If the sunshade is up and you go from park to drive, it will stay up unless you pause for a moment in reverse before moving the selector to drive.