Brake Malfunction Light - Comes ON
Bulletin: 84-5-4Date: Mar. '85
Ref. No. 85-173-5
SUBJECT: BRAKE LIGHT COMES ON
MODELS AFFECTED: 1984 CENTURY WITH 4.3L V-6 DIESEL ENGINE (LT7) FEDERAL ONLY
Some 1984 Century models equipped with 4.3L V-6 Federal diesel engines (LT7) may experience a slight vacuum leak which may be due to abrasion/puncturing of a section of a rubber hose, causing the brake light to come on. The leak is a result of a hole being worn in the vacuum hose between the vacuum regulator valve and the "T". If the brake light comes on, particularly if it is on only at idle, examine the vacuum hose for abrasion and a hole.. If worn through, replace and reroute as shown below. If not worn, check out the system as outlined in Section 5 of the Chassis Service Manual.
Vacuum Line:
Service Procedure
Rotate the "T" in the vacuum line until it is aimed at the left front headlamp. Use a thirteen and one-half (13 1/2) inch length of 7/32" I.D. vacuum hose cut from bulk hose, part number 3987364. Route the hose in front of the EGR solenoids as shown in Figure.