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-   -   Loud buzzing noise from under the dash? (https://www.toyota-4runner.org/3rd-gen-t4rs/278010-loud-buzzing-noise-under-dash.html)

The Cold War Kid 09-26-2019 10:01 PM

Loud buzzing noise from under the dash?
 
The noise comes on when I start then runs for 10 seconds or so. Maybe a vacuum pump? I have no idea.

The heater control does not work and the air passages are very slow to change with the control. Maybe this is something to do with the noise?

Anyone have this problem?

spartacus 09-26-2019 10:32 PM

could be the antenna motor.

brillo_76 09-26-2019 10:43 PM

Quote:

Originally Posted by The Cold War Kid (Post 3362567)
The noise comes on when I start then runs for 10 seconds or so. Maybe a vacuum pump? I have no idea.

The heater control does not work and the air passages are very slow to change with the control. Maybe this is something to do with the noise?

Anyone have this problem?

Might help to include the basic info of the vehicle your working on in your garage or signature that you know which vehicle are asking about. :-)

I am guessing you have a 1999-2002 4 runner that is doing this as the 1996-1998 dash was all non electric.

My 01 controls are functioning properly, so sorry I can't be able to help you on this one.:-(


Maybe look at the Factory service manual for your vehicle year troubleshooting guides will assist you in finding the cause of your noise. :-)

snydmax 09-26-2019 11:17 PM

Quote:

Originally Posted by spartacus (Post 3362585)
could be the antenna motor.



Rule this out first


Sent from my iPhone using Tapatalk

T.Tech 09-27-2019 12:04 AM

It could be the abs actuator motor if it’s one of the later ones.

The Cold War Kid 09-27-2019 06:29 AM

Quote:

Originally Posted by T.Tech (Post 3362614)
It could be the abs actuator motor if it’s one of the later ones.

Why would the ABS run when I start it up?

The Cold War Kid 09-27-2019 06:31 AM

Quote:

Originally Posted by spartacus (Post 3362585)
could be the antenna motor.

It wants an antenna, of course. I've heard that run. It's quiet, compared to this. This is a loud buzz - sounding for all the world like an air pump in an aquarium.

tgreenwood75 09-27-2019 07:00 AM

My 2001 does the same thing, 5+ second buzzing or sucking noise that ends with a click. Never really thought about what causes it because it's on startup and certainly seems "normal."

calimobber 09-27-2019 10:47 AM

Yeah it might just be the abs brake booster your hearing. Its a little motor pumping air. Its building pressure to assist with the brakes.

Pop the hood and turn the key, see of its coming from the brake acuator.

Joelzy 09-27-2019 10:51 AM

yeah that^
mine does it as well, if you turn the key on but dont start it it will usually still do it. drove me nuts at first but once i figured out thats what it was i got over it.

phattyduck 09-27-2019 01:00 PM

Quote:

Originally Posted by The Cold War Kid (Post 3362682)
Why would the ABS run when I start it up?

Still need to know the year and trim of your 4Runner to answer...

The 01/02 brake system is an electrically power hydraulic boost system that can make noises, especially when it is wearing out.

The earlier ABS system can/does make a quick noise soon after the brakes are released after startup. That's normal.

The Limited auto-AC servos can make noise if there are problems.

The auto-antenna can make noise when the radio is powered up.

-Charlie

nissanh 09-27-2019 01:10 PM

Newer 3rd gen 4runners have the expensive brake master pump which is 1/2 price of the 4runner's market price!
If you hear the sound for 30 minutes or less, that is normal as it is filling the booster with nitrogen gas. If it takes longer and/or hear the buzzing sound all times, then something is wring with the system and most likely it is not going to be a cheap repair.

The Cold War Kid 09-27-2019 10:16 PM

Quote:

Originally Posted by phattyduck (Post 3362851)
Still need to know the year and trim of your 4Runner to answer...

The 01/02 brake system is an electrically power hydraulic boost system that can make noises, especially when it is wearing out.

The earlier ABS system can/does make a quick noise soon after the brakes are released after startup. That's normal.

The Limited auto-AC servos can make noise if there are problems.

The auto-antenna can make noise when the radio is powered up.

-Charlie

I have a 2001 Sr5 2wd.

The master cylinder is massive. Scary!

The noise seems to come from the center of the car behind the dash. A humming... like an air pump.

T.Tech 09-27-2019 10:43 PM

Quote:

Originally Posted by The Cold War Kid (Post 3362682)
Why would the ABS run when I start it up?

The newer ones have a hydro booster that assists you when braking that abs motor runs to precharge the accumulator with pressurized brake fluid in case it needs to apply the brakes for the vehicles trac control or vsc. You can deplete the pressure by stepping on the brake about 20 times til the pedal feels different and then cycle the key to the on position and you will here it come on.

Mackalicious 09-28-2019 05:15 AM

Listen under the hood and see if its coming from the brake master. Theres an electric pump there.


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