SL L4-1.9L SOHC VIN 9 (1991)
Brake Light Switch: Description and Operation
PURPOSE
The transaxle controller, located inside the powertrain control module (PCM) receives five signals from various switches and signals and two
signals (vehicle speed and engine rpm), internally from the engine control module, also located within the PCM. The PCM uses this information
during control of the transaxle shift points.
OPERATION
The brake switch is a normally closed switch that sends a battery voltage signal to the PCM. If the transaxle is in 2nd gear and engine speed is low
and the brake switch opens, signalling the PCM that the brakes are applied, the PCM unlocks the torque converter. For 1993 this switch helps
determine if a downshift should occur while going down a hill.
LOCATION
The brake switch is mounted on the brake pedal bracket.
