Vacuum/Hydraulic Brakes - Diagnostic Procedure

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Article No. 83-13-23


BRAKE - VACUUM/HYDRAULIC SYSTEM - DIAGNOSTIC PROCEDURE
- VEHICLES WITH 6.9L AND 2.2L DIESEL ENGINES


LIGHT TRUCKS 1983 E, F AND RANGER

Diesel engine vehicles are equipped with a vacuum pump to provide vacuum for all vacuum actuated systems. Low vacuum in the vacuum system is indicated by the Brake Warning Light. Therefore, if the brake warning light comes on, either a hydraulic or a vacuum related concern could exist.

To determine whether it is hydraulic or vacuum system related, perform the following diagnostic checks:

^ Disconnect the vacuum sensor switch connector from the switch body;

^ ^If the brake light comes on when brakes are applied, the concern is related to the hydraulic system - see diagnostic procedure for brake warning light in the General Hydraulic Brake Systems, Service Manual, Section 12-01.

FIGURE 15:

FIGURE 16:

^ ^If the brake light does not actuate under the same conditions which it previously activated, a vacuum system concern is present. Perform the diagnostic procedure for vacuum system and vacuum booster, Figures 15 and 16.
OTHER APPLICABLE ARTICLES: None
WARRANTY STATUS: "INFORMATION ONLY"