Primary Brake Indicator Lamp
The primary brake indicator lamp will light on vehicles equipped with
hydraulic brakes and a continuous tone will sound if any of the following
conditions occur:
| • | There is insufficient brake fluid in the reservoir. |
| • | There is insufficient fluid flow in the hydro-boost system during
braking. |
| • | If the vehicle is equipped with antilock brakes, the Electronic
Brake Control Module (EBCM) notices a fault. |
The multifunction alarm module receives a ground signal from both the
brake fluid level switch and the EBCM through CKT 33, 495 and 494 (TAN/WHT).
The primary brake lamp is also connected through the TAN/WHT wire to the
level switch, the EBCM and the alarm module. The brake fluid level switch
is a float switch. The brake fluid level switch will close when the fluid
in the reservoir drops below a minimum level. The EBCM will provide a ground
path to the lamp and the alarm module if a diagnostic trouble code is set.
The brake fluid flow switch is connected to the multifunction alarm module
through CKT 475 and 1928 (LT BLU). If insufficient fluid flow is detected
in the hydro-boost system the flow switch closes in order to provide a ground
path to the alarm module.
Auxiliary Brake Indicator Lamp
The AUX BRAKE indicator lamp will light on vehicles equipped with hydraulic
brakes and a continuous tone will sound if any of the following conditions
occur:
| • | There is fluid flow in the hydro-boost system within four seconds
of the engine start. |
| • | No input is received from the stoplamp relay during braking. |
The brake fluid flow switch is connected to the multifunction alarm
module through CKT 475 and 1928 (LT BLU). If insufficient fluid flow is detected
in the hydro-boost system, the flow switch closes in order to provide a ground
path to the alarm module. The switch should be open during the engine start.
The multifunction alarm module receives the engine start voltage signal from
the starter relay through CKT 434 and 487 (ORN/BLK). The multifunction alarm
module receives the stoplamp relay voltage signal from the stoplamp relay
through CKT 489 (GRY).
