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Headlights - Automatic Ford LTD Crown Victoria I

Headlights 3 illustrations ~1025 words

DESCRIPTION & OPERATION

Autolamp system provides light sensitive automatic on-off control of headlights in conjunction with normal headlight switch operation. A light delay feature is also used to keep headlights on for a preselected time period after ignition is turned off and occupant has left vehicle.

Time lapse can be varied up to 4 1/2 minutes before lights turn off automatically. Autolamp system consists of a light sensitive photocell assembly, transistorized photocell amplifier, time delay control which includes an on-off switch and a headlight control relay.

Autolamp wiring parallels the regular light switch wiring. Headlight switch must be turned to "OFF" position, and the autolamp control turned to "ON" position for system to operate automatically. Autolamp control switch is located next to (Continental, Mark VII, Thunderbird and Cougar) or behind (all other models) headlight switch knob.

In normal operation, the system will turn headlights on when natural outside light available to photocell decreases below a predetermined level, such as at sunset. Also, the lights will automatically turn off if light level outside exceeds predetermined level during daylight hours.

System photocell is mounted under a group of perforated holes in upper instrument finish panel. Turning the autolamp control away from "OFF" position will increase lapsed time before headlights turn off after turning ignition switch to "OFF" position.

PHOTOCELL SENSOR AMPLIFIER

Two different photocell sensor amplifiers are used. Both have a label on the case providing adjustment instructions.

SYSTEM OPERATIONAL CHECK

Note. When a system malfunction is unknown, perform the following checkout procedure to isolate problem to a specific condition.

  1. Ensure that photocell lens of photo amplifier unit is clean and not obstructed. Make sure there is a clean, tight ground connection from circuit No. 57 of potentiometer unit at headlight switch.
  2. Make sure headlights operate normally with headlight switch. Check that autolamp relay connector is properly attached to relay.
  3. Place autolamp control in "OFF" position. Turn on the headlights using headlight switch. If lights do not operate, check out and correct the standard headlight circuit.
  4. If lights work okay, check autolamp fuse. If fuse is okay, proceed to CIRCUIT TEST in this article.

Note. Refer to illustrations for connector and terminal identification.

TAIL LIGHT CIRCUIT

Remove the connector from autolamp relay. Connect a test light between ground and Brown wire. Voltage should be present with headlight switch in "PARK" of "ON" position. If not, check continuity of wire to headlight switch.

HEADLIGHT CIRCUIT

Remove connector at autolamp relay. Connect a test light between ground and the Red/Yellow wire. Voltage should be present with switch in the "ON" position. If not, check continuity to the headlight switch, and if equipped, to high-low beam relay.

Scheme 1

Scheme 1: HEADLIGHT CIRCUIT
Scheme 1: HEADLIGHT CIRCUIT

On-Off Control Switch

  1. Using test light, test system ground. Connect one lead to ground and other lead to circuit No. 220 in delay control switch, with switch in "ON" position. If there is no continuity, perform steps 1) & 2) of POTENTIOMETER TEST.
  2. If potentiometer test is okay, check circuit no 220 between potentiometer connector and amplifier connector.

Delay Control Test

  1. Connect an ohmmeter between terminals No. 220 & 217 of the autolamp connector. (Scheme 3) With control in "MAX" position, reading should be approximately 200,000 ohms. If not perform step 3) of the POTENTIOMETER TEST.
  2. If the potentiometer is okay, check circuitry No. 217 for continuity between potentiometer connector and amplifier connector. If potentiometer does not check out okay, replace potentiometer.
  3. If all systems check out okay, but the system is still malfunctioning, replace the amplifier assembly.

Scheme 2

Scheme 2: Potentiometer Test (Continental, Mark VII, Thunderbird & Cougar)
Scheme 2: Potentiometer Test (Continental, Mark VII, Thunderbird & Cougar)
  1. Connect a test light or ohmmeter to terminals No. 6 & 4 on back of potentiometer. (Scheme 2)
  2. Check that there is no continuity when switch is in "OFF" position and that there is continuity when switch is in any other position.
  3. Connect the ohmmeter to terminals No. 5 & 6. Check that resistance gradually increases from 2500-4500 ohms at "OFF" position, to 140-260K ohms at "MAX" position.
  4. If the potentiometer fails any of the preceding tests, replace the potentiometer assembly.

Potentiometer Test (All Other Models)

  1. Using a test light, test for continuity between potentiometer connector circuit No. 57 and switch bracket. (Scheme 2) If no continuity exists, replace potentiometer.
  2. Check continuity between circuits No. 220 & 57 of the potentiometer connector while rotating the switch from "OFF" to "ON".
  3. Check for continuity between circuits No. 217 & 57 while rotating switch from "OFF" position to maximum time delay. Resistance for these tests should gradually increase from 2500-4500 ohms at "OFF" position, to 140-260K ohms at maximum time delay.
  4. On Town Car, check between circuits No. 507 & 508. If potentiometer fails any of the preceding tests, replace the potentiometer assembly.

Scheme 3

Scheme 3
Scheme 3

Note. If any part of the control switch test is unsatisfactory, replace potentiometer.

HEADLIGHT CONTROL RELAY

  1. Locate relay under right corner of instrument panel on Continental, under instrument panel on Cougar, Mark VII and Thunderbird, under instrument panel above ashtray on Crown Victoria, and on front upper edge of lower access hold in left hand cowl panel on Town Car.
  2. Disconnect the battery ground. Remove cowl trim panel on Town Car. On all models, remove screws attaching relay to mounting surface. Disconnect connector and remove relay. To install, reverse removal procedure.

SENSOR AMPLIFIER

Remove instrument panel top pad. Lift off pad and remove 2 screws holding sensor amplifier to the instrument panel. Remove connector. Reverse removal procedure to install sensor amplifier.

HEADLIGHT SWITCH & POTENTIOMETER

Note. Either headlight switch or potentiometer can be replaced separately. Both units must be removed as an assemble on all models except Continental, Mark VII, Thunder bird and Cougar. The assembly is serviced from front of the instrument panel on those models.

  1. Disconnect battery ground. Remove headlight know, bezels, and switch. Remove plastic spacer at end of potentiometer by pushing out with screwdriver.
  2. Remove strap securing wiring harness to switch Loosen retaining nut and washer and slide potentiometer out of switch. To install, reverse removal procedure.

Continental, Cougar, Mark VII & Thunderbird

Remove lens attaching screw and lens. Remove potentiometer attaching screws. Pull potentiometer assembly and wiring out of the instrument panel. Disconnect wiring connector. To install, reverse removal procedure.