Pinpoint Test H: The Speed Control Is Inoperative - No DTCS

WARNING: This page is about a different car, the 2004 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.

Test Step

H1 CHECK THE HORN SYSTEM

Verify the horn system operates by pressing the horn switch.
Does the horn system operate correctly?

Result / Action to Take

Yes

GO to H2.

REFER to HORN .

Test Step

H2 CHECK THE SPEED CONTROL ACTUATOR SWITCH ON

Key in OFF position.
Disconnect: Speed Control Actuator C122.
Measure the voltage between speed control actuator C122 pin 5, circuit 151 (LB/BK), harness side and ground, while pressing the speed control actuator switch ON.

Fig 1: Checking Speed Control Actuator Switch On
Courtesy of FORD MOTOR CO.
Is the voltage greater than 10 volts?

Result / Action to Take

Yes

GO to H3.

GO to H4.

Test Step

H3 CHECK THE SET/ACCEL SWITCH

Measure the resistance between speed control actuator C122 pin 5, circuit 151 (LB/BK), harness side, and speed control actuator C122 pin 6, circuit 848 (DG/OG), harness side, while pressing the speed control actuator switch SET/ACCEL.

Fig 2: Checking Set/Accel Switch
Courtesy of FORD MOTOR CO.
Is the resistance between 612 and 748 ohms with the switch pressed and greater than 10,000 ohms with the switch released?

Result / Action to Take

Yes

INSTALL a new speed control actuator. REFER to SPEED CONTROL SERVO . TEST the system for normal operation.

INSTALL a new speed control actuator switch. REFER to SPEED CONTROL SWITCH . TEST the system for normal operation.

Test Step

H4 CHECK CIRCUIT 151 (LB/BK) FOR AN OPEN

Key in OFF position.
Disconnect: Clockspring C203.
Measure the resistance between clockspring C203 pin 6, circuit 151 (LB/BK), harness side and speed control actuator C122 pin 5, circuit 151 (LB/BK), harness side.

Fig 3: Checking Circuit 151 (LB/BK) For An Open
Courtesy of FORD MOTOR CO.
Is the resistance less than 5 ohms?

Result / Action to Take

Yes

GO to H5.

REPAIR the circuit. TEST the system for normal operation.

Test Step

H5 CHECK THE CLOCKSPRING

Remove the driver air bag. Refer to AIR BAG RESTRAINT SYSTEMS .
If not equipped with remote audio/climate controls, measure the resistance between top of clockspring pin 1 and clockspring C218b pin 6. If equipped with remote audio/climate controls, measure the resistance between top of clockspring pin 6 and clockspring C218b pin 6.

Fig 4: Checking The Clockspring
Courtesy of FORD MOTOR CO.
Is the resistance less than 1 ohm?

Result / Action to Take

Yes

GO to H6.

INSTALL a new clockspring. REFER to AIR BAG RESTRAINT SYSTEMS . INSTALL the driver air bag. REFER to AIR BAG RESTRAINT SYSTEMS . TEST the system for normal operation.

Test Step

H6 CHECK THE SPEED CONTROL ACTUATOR SWITCH WIRE HARNESS

Measure the resistance between top of clockspring connector and speed control actuator switch connector as follows:

Top of Clockspring Connector	Speed Control Actuator Switch Connector
Pin 6	Pin 1
Pin 4	Pin 2

Fig 5: Checking Speed Control Actuator Switch Wire Harness

Courtesy of FORD MOTOR CO.

Are the resistances less than 5 ohms?

Result / Action to Take

Yes

INSTALL a new speed control actuator switch. REFER to SPEED CONTROL SWITCH . INSTALL the driver air bag. REFER to AIR BAG RESTRAINT SYSTEMS . TEST the system for normal operation.

INSTALL a new speed control actuator switch wire harness. INSTALL the driver air bag. REFER to AIR BAG RESTRAINT SYSTEMS . TEST the system for normal operation.