Subaru 2002 Impreza Service Manual page 334

MASTER CYLINDER
Brakes
A: BRAKE FLUID LEVEL SWITCH
The brake fluid level switch is located inside the brake fluid reservoir tank and causes the brake
system warning light on the combination meter to come on when the fluid level has dropped below
the predetermined level.
The switch assembly consists of a reed switch (normally open) and a permanent magnet that is
incorporated in a float.
When the brake fluid level is normal, the float is far above the reed switch, so the force of the mag-
net is unable to act on the reed switch. The warning light circuit, therefore, remains open.
When the brake fluid level drops to a level approximately 30 mm (1 .I 8 in) below the maximum level
and the float lowers accordingly, the magnet aligns with the reed switch, activating the reed switch
contact. The warning light then comes on to warn the driver of the situation.
The warning light may, although momentarily, illuminate even when the brake fluid level is normal
if the vehicle tilts or swing largely.
Ai-
(1)
Warning light
L
-------
-J
(2) Reed switch
NF0242
(3) Permanent magnet
B R-8