I know this has been covered a few times before but I have found a fault that hasn't been mentioned before when it comes to turning off that annoying brake warning light.

Car: E30 320i cabriolet
Problem: brake warning light on always. Annoying!!

Things I've tried based on other threads with no success:
- Joined brake sensors wires together, bypassing the plastic wear piece. Front left and rear right.
- Unjoined my connections and replace with OEM brake sensors.
- Removed instrument cluster and tested for voltage. (Managed to get the light to go out momentarily when the sensors cable was grounded. Produced 12v)

The completionist in me wanted functioning brake sensors and not some bypass solution like joining wires (didn't work anyway) or taking out bulbs.

Problem finally located. Electrical connector located under the rear seats (passenger side) had corrosion on the connectors. Lifted the seat to clean the leather and found a connected under some leaves and sand so thought I'd crack it open and give it a spray and scrub with contact cleaner. Voila problem solved. Hallelujah!! A clear dash at last.

Here's the picture of the location of the connector.

https://imgur.com/gallery/O04Tazu