(1) Set multimeter select switch to
(2) Connect positive (+) multimeter
lead to horn relay R3, terminal
(3) Connect negative () multimeter lead
to a known good ground.
(4) Turn ON ENGINE switch
(5) Press and hold horn button.
(a) If 22 to 28 vdc are not present,
replace horn relay R3 (Para 7-95).
(b) If 22 to 28 vdc are present, repair
wire 1168 (see schematic
Fig 2-36) or notify DS
(6) Release horn button.
(7) Turn OFF ENGINE switch.
(8) Press relay R3 completely into
(9) Install two ECB covers and 15 screws.
Remove all jewelry such as rings, dog tags, bracelets, etc. If jewelry or tools contact positive electrical
circuits, a direct short may result. Damage to equipment, injury or death to personnel may occur.
Circuit breakers CB5, CB6, CB12, CB20, CB22, CB23 and relays R3, R13 - R19, R26, R28, R32, R33
are always electrically hot and can cause severe injury to personnel. Care must be exercised when
working under the electrical circuit board cover.
(1) Press horn button and listen for horn.
(a) If horn does not operate, fault not
corrected. Release horn button
and notify DS Maintenance.
(b) If horn operates, fault has been
(2) Release horn button.