Circuit Description
The cruise control module applies voltage to the magnetic clutch when the cruise control system is engaged. The circuit between the cruise control module and the magnetic clutch in the actuator is interrupted by the stoplamp switch whenever the brake pedal is pressed.
Diagnostic Aids
Check for the following:
| • | Stoplamp switch out of adjustment, or faulty. |
| • | Open in the cruise control magnetic clutch. |
| • | An open, short, or ground in the WHT/BLK, RED/GRN, RED/BLK, GRN/BLK, or RED/YEL wires. |
An intermittent malfunction may be caused by a fault in the magnetic clutch electrical circuit. Inspect the wiring harness and components for any of the following conditions:
| • | Backed out terminals. |
| • | Improper mating of terminals. |
| • | Broken electrical connectors locks. |
| • | Improperly formed or damaged terminals |
| • | Faulty terminal to wire connections. |
| • | Physical damage to the wiring harness. |
| • | A broken wire inside the insulation. |
| • | Corrosion of electrical connections, splices, or terminals. |
Repair any electrical circuit faults that were found. Refer to Wiring Repairs .
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
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This step tests the resistance of the cruise control servo magnetic clutch circuit.
-
This step tests the stoplamp switch.
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Steps 7-12 isolates an open in the cruise control servo clutch circuit.
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This step tests the cruise control actuator arm for free movement with the magnetic clutch de-energized.
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This step tests the cruise control actuator arm for a malfunction with the magnetic clutch energized.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Cruise Control System Check performed? | -- | Go to Step 2 | |
Is the resistance within the specified range? | 35-45 ohms | Go to Step 3 | Go to Step 5 | |
3 | With the J 39200 still connected, press the brake pedal. Is the resistance reading within the specified range while the pedal is pressed? | Infinite | Go to Step 13 | Go to Step 4 |
4 |
Is the resistance within the specified range? | Infinite | Go to Step 5 | Go to Step 16 |
Does the resistance read infinite ohms while the pedal is pressed, and 0 ohms when the pedal is released? | -- | Go to Step 7 | Go to Step 6 | |
6 | Adjust or replace the stoplamp switch. Refer to Stop Lamp Switch Adjustment or Stop Lamp Switch Replacement . Is the adjustment or replacement complete? | -- | Go to Step 20 | -- |
With the stoplamp switch and cruise control module connectors still disconnected. Connect a J 39200 set to read resistance between terminal 8 of the cruise control module connector and terminal 3 of the stoplamp switch connector. Is the resistance within the specified range? | 0-2 ohms | Go to Step 9 | Go to Step 8 | |
8 | Repair the open in the GRN/BLK wire between terminal 8 of the cruise control module connector and terminal 3 of the stoplamp switch connector. Is the repair complete? | -- | Go to Step 20 | -- |
9 | With the stoplamp switch still disconnected.
Is the resistance within the specified range? | 0-2 ohms | Go to Step 11 | Go to Step 10 |
10 | Repair the open in the RED/YEL wire between terminal 4 of the stoplamp switch and terminal 3 of the cruise control servo connector. Is the repair complete? | -- | Go to Step 20 | -- |
11 |
Is the resistance within the specified range? | 35-45 ohms | Go to Step 12 | Go to Step 19 |
12 | With the cruise control servo still disconnected. Connect a J 39200 set to measure resistance between terminal 4 of the cruise control servo connector and ground. Is the resistance within the specified range? | 0-2 ohms | Go to Step 13 | Go to Step 17 |
Does the actuator arm move freely in both directions? | -- | Go to Step 14 | Go to Step 19 | |
Does the actuator arm move? | -- | Go to Step 18 | ||
15 | Repair the WHT/GRN wire between terminal 4 of the cruise control servo connector and ground. Is the repair complete? | -- | Go to Step 20 | -- |
16 | Repair the short to ground between the GRN/BLK wire of terminal 8 of the cruise control module connector and terminal 3 of the cruise control servo connector. Is the repair complete? | -- | Go to Step 20 | -- |
17 | Repair the WHT/BLK wire between terminal 4 of the cruise control servo and ground. Is the repair complete? | -- | Go to Step 20 | -- |
18 |
Is the replacement complete? | -- | Go to Step 20 | -- |
19 |
Is the replacement complete? | -- | Go to Step 20 | -- |
20 | Install and connect any components removed during diagnosis. Is the repair complete? | -- | -- |
