1. Disconnect the brake fluid level sensor connector from the master cylinder.
2. Inspect for continuity according to fluid level between the brake fluid level sensor terminals.

If not as indicated in the table, replace the reserve tank.

Brake Switch InspectionBack Up Light Switch Removal/Installation [C66 M R]
1. Remove the battery cover..
2. Disconnect the negative battery cable..
3. Remove the aerodynamic under cover No.2..
4. Remove in the order indicated in the table.
5. Install in the reverse order of removal.
1
Back-up light switch connector
2
...
Contact Authorized Mazda Dealer and Have Vehicle Inspected
If any of the following warning lights or the indicator light turns on/flashes, the system may
have a malfunction. Contact an Authorized Mazda Dealer to have your vehicle
inspected.
...
Power Outer Mirror Switch Inspection
1. Disconnect the negative battery cable..
2. Remove the following parts:
a. Inner garnish.
b. Front door trim.
c. Switch panel.
3. Verify that the continuity between the power outer mirror switch terminals
is as indicated in the table.
If not as indicated in the table, replace t ...