The brake sensor consists of 2 parts. The first is a small wire running below the lever which controls the rear brake. It is held in a neoprene sleeve glued to the brake lever and can be slid back and forth within this sleeve in order to give you some adjustment. On G1 Consoles this wire connects directly to the console. On a G2 console its the small wire running from the throttle unit to the brake lever.
The second part of the brake sensor is a magnet glued or fixed onto your brake lever by a screw.
Check to make sure you have both the magnet on your brake lever and the brake sensor. To make a proper adjustment, plug your brake sensor wire in and slowly pull the sensor away from the magnet until you see a "G" appear on the console display. Then move it back slowly until just when that "G" disappears.
Test this adjustment by pulling the rear brake lever. The "G" should show on the console when the lever is pulled and disappear when the lever is released. Done!
Magnet installed incorrectly
Occasionally people install the magnet way too far away from the brake sensor. The magnet should never be more than a half inch away from the brake sensor. If it is, it is not going to work. Re-install it properly according to your installation manual.
Reversed brake sensor
If your brake sensor acts opposite from what is described above - it turns the console to "G" mode when it is brought close to the magnet - you have what's called a "reversed brake sensor". If that's not what you ordered or need, contact your dealer for clarification.
Throttle connection issue
If you have a G2 Console and are using the separate throttle unit, disconnect the throttle and plug the brake sensor wire directly into the console. Make the same adjustment described above. If it works now then the signal is not making it through the throttle. Clean all connections thoroghly and try again. If it still doesn't work the throttle unit should be replaced.
Brake sensor is disabled
This is pretty unlikely but can happen. You'll need to enter code 2006 and change the setting. Here's how to access that code:
There are slightly different processes for accessing console codes depending on whether you have a G1 or G2 console. Not sure which you have? Check here to find out.
G1 Console - Accessing codes
G2 Console - Accessing code
Once you've accessed code 2006 you will see some abbreviations related to the work brake like "BRK" and the word "off" or "nc".
This one is pretty uncommon, assume this is the case only if you've done all steps described above. If you plugged the brake sensor wire in but you never get a "G" on the console, regardless of how far away you pull it, you may need to get a new brake sensor.