Hello, this is my first post here. I'm glad I found this place!
I've searched for an answer on the site to no avail, so here it goes.

My '89 Laredo makes a weird electronic, muted buzzing noise only when
my brake pedal is not depressed. If I press down the brake pedal it stops.
It appears to emanate from beneath the driver's side dash by my feet.
The noise is barely audible while driving down the street, but it is there all
the same... mocking me, taunting me.... What is it and how do I kill it?

 

can you pin point the area its coming from?

 

Yes, as I put my head by where my feet go on the driver's side I can hear it loudly, but the acoustics are such that it sounds like it comes from everywhere under there.

 

have you removed the buzzer yet , like key in ignition,seat belt and lights on buzzer think it plugs into side of fuse box by left foo

 

left side of fuse box its black...

 

Ok I'll try it tomorrow and report back what happens. Thanks for the info! I think mine is big and blue.

 

I removed that buzzer on the fuse panel and the sound didn't stop.
I then located the source of the high-pitched electronic buzzing/whining sound. It comes from this thing by my feet. I know it has to do with the brakes, but I'm at a loss as to what it is and why it's making that annoying sound.

 

What happens if you unplug the wires?

That wiring doesn't look factory and I don't ever remember seeing anything like that up under the dash.

 

X2 do you have cruise controll? We're do they lead

 

I believe that's the early cruise control speed sensor. It's inserted into the speedometer cable.

 

what he said^ is that hooked into speedo cable?

 

It might be an aftermarket cruise control. I parted out an 88 or 89 and it's cruise sensor was totally different from that one in the photo.

 

Sorry about the long delay between replies (I moved and had to rehab the "new" house which took forever). I discovered later that this particular piece wiring was introduced during a cruise control recall. I unplugged the unit, turned the car on, turned the car off, plugged it back in, the noise went away and I haven't heard it since.