ML320 Build Date October 2000. Brake wear sensor started to light up intermittently then more often and in the last week for several times, an audible pitch noise sounded when the wear sensor(both handbrake and sensor lights) lit up.

Bought a set of new front brake pads - with new sensor wire pre-fitted to the passenger side pad set and installed these new pads to the front 2 wheels. (Old pads had over 1/4" left on them).

Fitted the pads making sure the sensor wire clipped in ok and was not damaged in the fitting process.

Driving the car now - the sensor light (both brake and wear sensor light) still light up intermittently.
Today I had to brake hard and almost engaged the ABS and the sensor lights lit up and the audible pitch sounded at the same time.

Brake fluid is up to the full level.

Please, gents, what do you think I should look for?

Rear pads?

Thank you for the hint.
Removed the rear passenger side wheel and found the sensor wire was almost worn through .
Wire was dislodged from the holding bracket and was hanging loose and rubbing against the rotor.

What have I learnt?
When getting a similar warning appearing on the console, check the electrics before presuming the fault is mechanical.

I now have a new front & rear set of pads ready for use.

Sorry guys, I am rather embarrassed.

According to my Service Advisor a good rule would be every 2 replacements of the front pads the rear should be replaced as well. Unless of course you have extra mullah then you can change both front and rear pads together all the time.

So 1st change just front brake pads. 2nd change of front , change front and rear pads. 3rd change of front skip rear again, 4th change of front change with rear pads. So on and so forth....