Pinpoint Test E: A Single Illumination Source Is Inoperative

WARNING: This page is about a different car, the 2010 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.

Refer to appropriate SYSTEM WIRING DIAGRAMS article, Cluster and Panel Illumination for schematic and connector information.

Normal Operation

The lighting control module (LCM) supplies a variable pulse-width modulated (PWM) voltage to the dimmable switches and components through circuit 484 (OG/BK). The non-dimmable switches and components receive voltage through circuit 964 (DB/LG) from the central junction box (CJB) when the ignition switch is in the ACC or RUN positions. The switches and components are grounded through circuit 57 (BK).

This pinpoint test is intended to diagnose the following:

Wiring, terminals or connectors
Headlamp switch
Adjustable pedal switch
Traction control switch
Message center switch
Clock
Front cigar lighter
LH rear cigar lighter
RH rear cigar lighter
Exterior mirror control switch
Driver door lock control switch
Passenger door lock control switch
Driver heated seat switch
Passenger heated seat switch
LH rear heated seat switch
RH rear heated seat switch
Audio unit
Rear audio/climate control switch

PINPOINT TEST E: A SINGLE ILLUMINATION SOURCE IS INOPERATIVE

NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

E1 CHECK FOR VOLTAGE TO THE INOPERATIVE ILLUMINATION SOURCE

Disconnect: Inoperative Illumination Source
Key in ACCESSORY position.
Place the headlamp switch in the PARKING LAMPS ON position.
Rotate the instrument panel dimmer switch to the full illumination position.

Measure the voltage between the inoperative illumination source and ground as follows:

Inoperative Illumination Source	Connector-Pin	Circuit
Headlamp switch	C205a-2	484 (OG/BK)
Adjustable pedal switch	C2089-5	484 (OG/BK)
Traction control switch	C280-3	484 (OG/BK)
Message center switch	C253-7	484 (OG/BK)
Clock	C2016-2	484 (OG/BK)
Front cigar lighter	C2031-2	484 (OG/BK)
Cigar lighter LH rear door	C714-2	484 (OG/BK)
Cigar lighter RH rear door	C814-2	484 (OG/BK)
Exterior mirror control switch	C527-3	964 (DB/LG)
Driver door lock control switch	C505-5	964 (DB/LG)
Passenger door lock control switch	C605-5	964 (DB/LG)
Driver heated seat switch	C538-5	964 (DB/LG)
Passenger heated seat switch	C630-5	964 (DB/LG)
LH rear heated seat switch	C722-5	964 (DB/LG)
RH rear heated seat switch	C822-5	964 (DB/LG)
Audio unit	C290a-3	484 (OG/BK)
Rear audio/climate control switch	C3161-5	484 (OG/BK)

Is the voltage greater than 10 volts?

YES : Go to E2.
NO : REPAIR the circuit in question. TEST the system for normal operation.

E2 CHECK FOR GROUND TO THE INOPERATIVE LAMP(S)

Key in OFF position.
Place the headlamp switch in the OFF position.

Measure the resistance between the inoperative lamp and ground as follows:

Inoperative Illumination Source	Connector-Pin	Circuit
Headlamp switch	C205a-1	57 (BK)
Adjustable pedal switch	C2089-4	57 (BK)
Traction control switch	C280-7	57 (BK)
Message center switch	C253-2	57 (BK)
Clock	C2016-5	57 (BK)
Front cigar lighter	C2031-3	57 (BK)
Cigar lighter LH rear door	C714-3	57 (BK)
Cigar lighter RH rear door	C814-3	57 (BK)
Exterior mirror control switch	C527-8	57 (BK)
Driver door lock control switch	C505-3	57 (BK)
Passenger door lock control switch	C605-3	57 (BK)
Driver heated seat switch	C538-1	57 (BK)
Passenger heated seat switch	C630-1	57 (BK)
LH rear heated seat switch	C722-1	57 (BK)
RH rear heated seat switch	C822-1	57 (BK)
Audio unit	C290a-6	57 (BK)
Rear audio/climate control switch	C3161-3	676 (PK/OG)

Is the resistance less than 5 ohms?

YES : INSTALL a new switch or component in question. TEST the system for normal operation.
NO : REPAIR the circuit. TEST the system for normal operation.