brake system warning light does not light up even when the brake fluid in the tank decreases

1. Brake system warning light does not light up even when the brake fluid in the tank decreases diagnostics

1. Pre-check and visual inspection

1) Check for any interference from aftermarket electronic components such as two-way radios or lights.

Turn OFF or remove any aftermarket electronic components to ensure that there is no influence on inspections or operations.

2. Components inspection

1) Inspect the brake fluid switch.

Refer to "4.Brakes 4B.Brake System brake master cylinder inspection".

Replace if an abnormal condition is found in the brake fluid switch.

2) Inspect the instrument panel cluster.

Refer to "9.Body, Cab, Accessories 9E.Instrumentation, Driver Info. instrument panel cluster diagnostics".

If a malfunction is found in the instrument panel cluster, replace it.

Caution

If the instrument panel cluster is replaced with a new one, write the vehicle information to the instrument panel cluster.

Refer to "9.Body, Cab, Accessories 9E.Instrumentation, Driver Info. instrument panel cluster removal".

Refer to "9.Body, Cab, Accessories 9E.Instrumentation, Driver Info. instrument panel cluster installation".

Refer to "9.Body, Cab, Accessories 9E.Instrumentation, Driver Info. instrument panel cluster setting".

3. Circuit inspection

1) Check that the ground point is normal.

Repair or clean any ground points that are improperly installed or significantly dirty.

2) Check that the harnesses and connectors are normal.

Inspect for the following circuits for an open circuit, short, poor connections at the connectors, and abnormal conditions such as worn or bent harnesses.

Between the instrument panel cluster and the brake fluid switch

Caution

When checking the continuity between the harnesses, disconnect the battery negative terminal.

Refer to "201.General Information 14A.Service Information Guide Preliminary and post procedures".