Hi.
The noise seems to be some solenoid, relay or actuator behind the glove box. What is it ?

 

Abs acting up. Is it a pulse noise?

 

Shift lock solenoid? Listen close to the shifter, with the truck in Park.

 

Thanks and sorry for the delay. My internet access is not doing well.

It is not by the shifter, it is behind the glove box, and happens after the four amigos came up.
It is some clunk noise when pressing the brake pedal, as commanded by the brake switch.

As related information, the wheel speed sensors measured and tested = OK ; the shuttle valve switch measured, tests 3000 ohm = OK.

 

If your 3 amigos are on, having the codes scanned by someone with the appropriate scanner would go much further in finding out what's wrong than chasing a sound. Most of the newer advanced scanners (Snap On Solus, Autologic, etc.) can, as well as the ABS Amigo.

 

Sounds like the normal ABS self test, its a Disco thing happens everytime the brake is released. Kinda sounds like an electric holywood servo going off for a second and a half or so changing tones a few time during the noise?

 

Thanks.
No tones, just a momentary clunk at pedal pressing.
I have the four amigos after replacing rear brake pads; wheel sensors and shuttle valve switches in the modulator confirmed healthy, by reading resistances and watching sinewave signals entering the Wabco module with an inboard oscilloscope hooked to each wheel twisted pair while driving. (Yes, my thing is electronics)
I suspect it has to be related to pushing back the calipers for brake pads insertion, as nothing else was mishandled.
Finding/buying the ABS error code reader has not happened yet. I do not know if the problem has gone away by itself, Disco2 works and brakes fine, but the amigos are latched and need reading/clearing.
If there was a way to reset the Wabco module would be great, as disconnecting battery does not clear it nor the 'amigos' status as it does with the ECU.

 

I'm sorry... four amigos?

I'm familiar with the (ABS), (TC) and Hill Descent errors coming on in tandem... what's the 4th indicator you're seeing?

 

The actual brake light.


I believe its the neutral safety switch on the transmission. I hear the exact same thing when in park, but not in drive.....

 

If it's the "BRAKE" light, then this isn't an amigo.

The three amigos are called as such because they all rely on the ABS system to be functioning properly. If there's an error condition with the ABS system, it will cause render the hill descent and traction control features inop as well.

The BRAKE light indicates two things:
- Your parking brake is engaged.
- You are dangerously low on brake fluid.