Operation and Diagrams
(see diagrams and illustrations on bottom)
SEQUENTIAL TURN SIGNAL CIRCUIT OPERATION
The sequential turn signal circuit is unique in its operation. Thestoplight circuit will also be covered since it is wired into the turnsignal circuit.
The basic components (Illus. 17001.3- 10) of the s~juentia1 turn signaland stoplight circuits are the turn signal switch, mounted on the steeringcolumn; the turn signal indicator relay, mounted on the steering columnsupport hracket the stoplight switch, mounted on the brake pedal support,and the turn signal relay, stoplight relay and turn signal flasher andmotor unit which are wrapped in soundproof insulation and mounted in theluggage compartment behind the left fender trim panel.
The flasher assembly consists of a motor, three cams on a shaft andthree sets of contact points. The three cams axe staggered and each setof contacts is connected to one of the three rear light bulbs through theturn signal relay.
When the turn signal switch is actuated, either right or left, a circuitis completed to the turn signal relay to the respective right or left sidesolenoid. A set of four contact points is actuated by the solenoid to connectthe rear lights to the flasher and motor circuit. Three contacts connectthe three rear lights and one contact connects the front turn light.
The following wires are connected together at the turn signal switchwhen the switch is put in the right- hand position: (694, 362) and (8,441, 458). In the left-hand position, wires (694, 363) and (8, 440, 458)are connected together.
When the turn signal switch is actuated, either right or left, the circuitis completed to the flasher motor and to the flasher cam contacts. Thisstarts the motor in operation and the cams begin to rotate. As the camsrotate, the three sets of contacts are closed in sequence and the threerear lights are illuminated in sequence beginning at the inboard light,then the center light and then the outboard light. All three lights goout at the same time and the cycle is repeated, as long as the turn signalswitch is closed to indicate a turn. The front parking light bulb flashesat the same time as the center rear bulb.
When the turn signal switch is canceled, the light bulbs go out immediately.
The turn signal indicator lights are controlled by the turn signal indicatorrelay (a current relay). The relay is adjusted so that it will open a setof contacts whenever the four turn signal light bulbs are on. The relayremains closed and the indicator light is illuminated until the four signallights are all on and current flow is heavy enough to cause the contactsto open, The relay contacts then open and the indicator light goes outuntil all four exterior lights are off simultaneously. The relay contactsthen close to illuminate the indicator light If one or more of the exteriorlight bulbs are not functioning (burned Out), the relay contacts will remainclosed and the indicator light will remain on.
The brake light circuit in this sequential system is connected intothe circuit differently than in the standard turn signal circuit. In thestandard circuit, the brake lights are connected to the turn signal circuitat the turn signal switch. In the sequential system, the brake lights areconnected to the turn signal circuit in the turn signal relay. When theturn signal switch is in the neutral position, no electrical connectionis made at the turn signal switch and the turn signal relay solenoids areat the rest position. Six contact points in the turn signal relay are connectedelectrically together and complete the circuit from the brake light switch,through the stoplight relay* to the spotlights.
The wiring schematic for the exterior lights, turn signals and emergencyflasher systems is included in the Electrical Diagrams Section.
Refer to Illus. 17001.3-11 for the wiring schematic~
ONE LIGHT, EITHER FRONT OR REAR, DOES NOT OPERATE
First, eliminate the possibility of any problems which can be foundby a visual inspection and the possibility of a burned- out bulb. The onlypossible part left to check is the turn signal relay in the taped package.
If the bulb and socket and wiring has continuity to the turn signalrelay and all of the lights but one operate, then make a test for powerat the relay terminal of the bulb in question. If no power is available,the turn signal relay switch mechanism is defective. This test is madewith the ignition switch ON and the turn signal switch in the proper position.
ONE SET OF TURN SIGNAL LIGHTS DOES NOT OPERATE — BRAKE LIGHTS OPERATE
This problem can be isolated to the turn signal switch, the turn signalrelay or the wiring from the switch to the relay.
Make a test for power at the turn signal switch disconnect terminalswith the turn signal switch in the position in question and the ignitionswitch ON. If there is no power at the terminals leading to the motor,turn signal indicator relay, or the turn signal relay; the turn signalswitch is defective. If power is available to all these terminals, thetrouble can be isolated to the wire leading to the turn signal relay coilor to the relay unit itself. Make a test for power at the turn signal relaydisconnect at the terminal leading from the switch. If power is not available,the wiring has a defect between the switch and the relay. If power is available,the turn signal relay is defective. The wire in question leads to thecoil in the relay which actuates one side of the relay and switches thecircuit from the stoplight wires to the turn signal wires.
* The stoplight relay was only used on early production.
ONE OR BOTH SETS OF STOPLIGHTS DO NOT OPERATE — TURN SIGNAL LIGHTS OPERATE
If one set of brake lights does not operate and the turn signals dooperate, the problem has to be a defective turn signal relay.
If all stoplights do not operate, the problem can be at the stoplightswitch, stoplight relay, turn signal relay or the wires leading betweenthe three components.
Make a test for power across the stoplight switch terminals with thebrake pedal depressed. If there is no power, the stoplight switch is defective.If there is power, make a test for power at the stoplight relay to determineif it has a good ground connection and if it is operating. If there isno power, there is a defect in the wiring between the stoplight switchand the stoplight relay, If there is power and the relay is functional,check the wire and its connections between the stoplight relay and theturn signal relay. If the wire is good, there is a defective con -nectioninside the turn signal relay.
ALL TURN SIGNAL LIGHTS DO NOT OPERATE —ALL PARKING LIGHTS AND STOIPLIGHTSDO OPERATE
This problem will require visual, audible, and power tests at all ofthe sequential turn signal components. Since the stoplights operate, wecan temporarily eliminate the turn signal relay as the trouble spot Usingthe circuit diagrams as reference, make tests for power at the turn signalswitch first in both left and right positions to determine if power isavailable from it to the turn signal indicator relay, the flasher and motorunit and the turn signal relay. All tests are made with ignition and turnsignal switch ON. After eliminating the turn signal switch as the troublespot, test for power at the turn signal indicator relay to determine ifit is operating properly. Next, go to the flasher and motor unit and testat all of its leads for power. The last possible unit is the turn signalrelay.
Test the components in the above mentioned order, namely:
1. Turn signal switch
2. Turn signal indicator relay
3. Flasher and motor unit
4. Turn signal relay
Test the components power source lead(s) and then the power outlet lead(s)before assuming the component is defective, because the trouble may bein the wiring between components.
EMERGENCY WARNING FLASHER
The emergency warning flasher circuit utilizes the sequential flasherand motor unit as the flashing element instead of a heavy-duty flashercan. In addition, the system requires Only two double-pole relays versusthree relays in the past system.
As shown in the flasher and motor unit schematic, one set of contactpoints and one operating cain has been eliminated. This set of contactswas used as the parking switch for the sequential motor, the motor willnow park in any position.
The switch for the emergency warning flasher circuit has been relocatedto the right-hand side of the steering column, opposite the turn signalswitch lever. Both switches are in fact a one unit assembly.
As in the past, the turn signal circuit can only be operated when theignition switch is in the ACO position or the ON position. The emergencywarning flasher circuit receives power directly from the battery througha separate circuit breaker and can be operated independently of any othercircuit
Illustration 17001.3-12 shows the necessary components and wiring forthe emergency warning flasher circuit The switch is shown in OFF positionand the relays in the de- energized position.
When the switch is pushed in to the ON position, several circuits arecompleted:
1. Wire 441 completes the circuit to the right-hand solenoid in theturn signal relay. This connects the right-hand front and rear lights tothe flasher motor circuit.
2. Wire 440 completes the circuit to the left-hand solenoid in the turnsignal relay. This connects the left-hand front and rear lights to theflasher motor circuit.
3. Wire number 514 opens the circuit through the coils of relays Aand B. This de-energizes the relays (if the ignition switch is ON) andcloses the contact points. NOTE: These two relays are energized when theignition switch is in ACC or ON position, when energized the contact pointsopen.
4. Wire number 458 completes the circuit through the coil and contactpoints of the turn signal indicator relay. Wire 459 in turn completes thecircuit to the flasher motor and starts it turning.
o. Wire 694 completes the circuit through the contact points of relayA and on through wires 362 and 363 to the right- and left-hand indicatorbulbs.
6. Since the contact points of relay B are closed, wires 4364 437A and438A are in effect a single wire circuit This is done to combine the threesequential signals, coming from the flasher, into a single flashing signal.
The flashing signal is then sent through the closed points of the turnsignal relay to all six rear lights and two front lights. The two indicatorlights on the dash panel go out each time the current draw from the eightexterior lights causes the turn signal indicator relay contact points toopen. The indicator lights flash at the same speed as the exterior lights,but at opposite times.
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