Ford COUGAR 1968 Shop Manual page 643

15-28
GROUP 15
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Lighting System, Horns And Instruments
unit consists of a motor and a three
toothed cam. As the cam turns, it
operates the contacts to each of the
three rear light bulbs in sequence,
thru the sequential turn signal relay.
OPERATION
When the ignition switch is turned
ON, the turn signal switch is ener-
gized. Also the solenoid in the emer-
gency warning relay is energized,
closing two sets of contacts which
provide circuits for the two inboard
and two outboard lights on the rear
of the vehicle.
When the turn signal switch lever,
located on the left side of the steer-
ing column, is moved to indicate a
turn, the appropriate solenoid is
activated in the sequential, turn sig-
nal relay. The sequential turn signal
relay solenoid breaks the stop light
circuit contacts and establ~shes a bank
of contacts to the lights which indi-
cate the turn. At the same time, the
circuit to the sequential turn signal
flasher is completed and starts opera-
tion of the flasher motor and cam.
As the cam rotates, the circuit to each
of the three rear lights, in sequence,
is completed thru the sequential re-
lay. The lighting sequence may start
at any one of the lights and progress
until the cycle is completed, at which
time the normal cycle of inboard,
center and outboard would start.
Each light will then remain illum-
inated until the cycle iicompleted. Then
all three lights go out at the same
time and the cycle
is
repeated as
long as the turn signal switch is in
the closed position. The front park-
ing light bulb flashes in sequence with
the center rear light bulb. When the
turn signal switch is canceled, the
light bulbsgo out immediately.
The instrument panel turn indica-
tor lights are controlled thru the con-
tacts in the turn signal switch. Two
separate indicator light feed circuits,
combine to provide a constant feed
circuit to the right or left coil in the
turn signal relay. This provides a
constant feed to the indicator bulb
of the turn selected. The turn signal
relay determines the flash time of the
indicator bulb. When the four bulbs
are on in the sequential cycle, the in-
dicator bulb ground circuit is broken
by the turn signal relay, resulting in
the indicator bulb flash effect.
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2 DIAGNOSIS AND TESTING
FIG. I-Horn
Trouble Diagnosis G u i d e
HORNS DO NOT SOUND
ONE HORN FAILS
T O OPERATE
HORNS OPERATE
CONTINUOUSLY
Verify the complaint.
light switch to horn button.
I . Loose connections at horn but- 4. Horns defective or out of ad-
ton contact. justment.
2. Open wire (yellow-green stripe) 5. Defective circuit breaker in
from horn to horn button. headlight switch.
3. Open wire (yellow) from head-
Verify the complaint. 2. Horn defective or out of ad-
I. Broken or loose wire to the justment.
horn (blue-yellow).
Verify the complaint.
I.
Horn button defective.
FIG. 2-Sequential
Turn Signal Trouble Diagnosis Guide-External Signals
ALL TURN SIGNALS
INOPERATIVE
ONE O R BO'TH FRONT
TURN SIGNAL DOES NOT
OPERATE (TURN INDICATOR
LIGHT REMAINS ON AND
REAR LIGHTS OPERATE)
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Verify the complaint. 6. Open circuit in turn signal re-
I.
Defective fuse. lay (dash panel).
2. Open circuit between fuse panel 7. No electrical feed (open wire)
and turn signal switch. between the turn signal relay (instru-
3. Poor ground for turn signal ment panel) and the sequential flasher
relay and sequential flasher in lug- in the luggage compartment.
gage compartment.
8. Defective sequential turn signal
4. Defective turn signal switch. flasher assembly (luggage compart-
5. Open circuit betweed turn sig- ment).
nal relay (dash panel) and turn sig-
nal switch.
Verify the complaint. 3. Open circuit between the bulb
I. Turn signal filament of bulb and the turn signal relay.
burned out. 4. Defective turn signal relay or
2. Corrosion o i foreign matter on
wiring in the luggage compartment.
bulb or socket terminal.