Brake Booster Vacuum Pump (Diesel)

Vacuum is supplied to brake booster on diesel engine models by belt driven vacuum pump mounted on engine near alternator. A low-vacuum switch actuates the brake warning light when vacuum is below a specified level.

The switch senses vacuum through a fitting in the intake manifold that intercepts the vacuum flow from the pump. Brake warning light will illuminate until vacuum builds to proper level. Vacuum pump is not serviceable and must be replaced if defective.