Loud buzzing noise from under the dash?

[The Cold War Kid]

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]

could be the antenna motor.

 

[brillo_76]

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]

could be the antenna motor.

Rule this out first


Sent from my iPhone using Tapatalk

 

[T.Tech]

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

 

[The Cold War Kid]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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

 

[rightyouareken]

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.

Once the noise shuts off after ~10-30 seconds or so, pump the brake pedal 5-15 times. If the noise starts up again, that's your brake booster/pump which is attached to your master cylinder. If you do feel something is wrong with it, PM me, there are some sub assemblies that you can buy to save some money potentially. I recently had to replace the whole kit and kaboodle on my 2002 after much diagnosis and research.

If the noise doesn't reoccur no matter how much you press the brake pedal, it was probably your antenna motor or something else.

 

[The Cold War Kid]

Once the noise shuts off after ~10-30 seconds or so, pump the brake pedal 5-15 times. If the noise starts up again, that's your brake booster/pump which is attached to your master cylinder. If you do feel something is wrong with it, PM me, there are some sub assemblies that you can buy to save some money potentially. I recently had to replace the whole kit and kaboodle on my 2002 after much diagnosis and research.

If the noise doesn't reoccur no matter how much you press the brake pedal, it was probably your antenna motor or something else.

Right - will do. Got involved with the driveshaft today. I'll start a thread about it

 

[BoomerBob]

I hear this noise on mine too. Sometimes it will run for a while so knowing this money pit; it's probably going out too. Not sure where the Toyota reliability got its reputation but I'm not feeling it with my 01. Maybe just got a lemon. Probably a $500 fix for this too in my future.

Does anyone know if the brakes work without this ABS pump working? I honestly don't care about ABS brakes. Great if a vehicle has them and they work but I've driven decades of cars and trucks without them so no biggie to me.

Abs pump brake master cilinder for 01-02 toyota 4 runner | eBay

 

[The Cold War Kid]

I hear this noise on mine too. Sometimes it will run for a while so knowing this money pit; it's probably going out too. Not sure where the Toyota reliability got its reputation but I'm not feeling it with my 01. Maybe just got a lemon. Probably a $500 fix for this too in my future.

Does anyone know if the brakes work without this ABS pump working? I honestly don't care about ABS brakes. Great if a vehicle has them and they work but I've driven decades of cars and trucks without them so no biggie to me.

Abs pump brake master cilinder for 01-02 toyota 4 runner | eBay

Noise turned out to be the heat selector motor. It turns on the heat and opens the heater door when you move the temp control. There are threads about that - I seem to have deleted those bookmarks 'cause mine is fixed. Maybe someone will chime in with those threads?

This was a zero dollar fix - I bought a tube of gorilla super glue - that's it. If you pay people to fix your vehicles methinks NO 19 year old will please you.

 

[BoomerBob]

Noise turned out to be the heat selector motor. It turns on the heat and opens the heater door when you move the temp control. There are threads about that - I seem to have deleted those bookmarks 'cause mine is fixed. Maybe someone will chime in with those threads?

This was a zero dollar fix - I bought a tube of gorilla super glue - that's it. If you pay people to fix your vehicles methinks NO 19 year old will please you.

I do 90% of my own work of course. Only been working on cars and motorcycles for 48+ years. I don't know about the heat selector motor but I can say when I bled the brakes on the rig the other day; I had to turn the key on for this motor to kick in so they would bleed properly so that confirmed it's a brake motor. I provided a link to a rebuilt one on ebay for reference in my previous post.

I will keep your issue with the heater door in mind though if I hear any motor noises coming from the center of the dash. That is where you heard it right? Center dash?