- Take off the cap: switch on the power by pressing "power" button shortly. "batt 0%" shall light up, LED illumination shall light up. If not, please change the battery.
- Press "switch" button to change the brand of brake fluid: (1) Shortly press the "switch" button to change the brand. (2) Press and hold "switch" for more than 3 seconds to reset the tester (For example, reset the tester when multiple brake fluid with same brand is going to be tested).
- Dip the tester into brake fluid until the fluid reach the edge of the plastic. (Make sure the two metal probes are fully immersed.) It will take about 1 second to measure the fluid. Tester will automatically shut down after 20 seconds.
- Read LED indication:
- Green: Battery OK.
- Green/Yellow: Fluid contains less than 1% of water.
- Green/Yellow/Yellow: Fluid contains less than 2% of water.
- Green/Yellow/Yellow/Red: Fluid contains about 3% of water, change the brake fluid.
- Green/Yellow/Yellow/Red/Red: Fluid contains about 4% of water, dangerous! Change the brake fluid immediately.