14827 Mercruiser STUD

Illustration 1 g02600223
Schematic of the switch inputs and wiring (control assembly output connectors)
Illustration 2 g02602058
Schematic of the switch inputs and wiring (control assembly input connectors) if equipped with A4 ECM
Illustration 3 g06325432
Schematic of the switch inputs and wiring (control assembly input connectors) if equipped with A5 ECM
Illustration 4 g02602116
Location of the connectors at the control box that are for the fuel control (typical top front engine view)
(1) Control assembly input connector (secondary ECM)
(2) Control assembly output connector
(3) Control assembly input connector (primary ECM)
(4) J1/P1 connector (primary ECM)
(5) J1/P1 connector (primary ECM)
(6) Engine interface connector
Illustration 5 g02602257
Location of the connectors at the control box that are for the fuel control (typical top front engine view)
(7) Terminal strip at the display panel
(8) Starter override switch (RH)
(9) Starter override switch (LH)
(10) Manual select switch for starter selection
(11) Low idle select switch
(12) Engine protection override switch
(13) Rapid start/stop switch
(14) Manual prelube
Table 1
Troubleshooting Test Steps Values Results
1. Check the Electrical Connectors and the Wiring
A. Remove the electrical power from the Electronic Control Module (ECM).
B. Thoroughly inspect connectors (1 through 6) and the engine interface connectors at the display panel. Also, thoroughly inspect terminal strip (7) and the connections for the suspect switch. Refer to Troubleshooting, "Electrical Connectors - Inspect"
C. Perform a 45 N (10 lb) pull test on each of the wires in the circuit for the suspect switch.
D. Check the allen head screw on each ECM connector for the proper torque. Also, check the allen head screw on the customer connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
E. Check the harness and wiring for abrasions and for pinch points from the battery to the ECM.
Connectors
Results: The wiring and connectors appear to be OK.
Proceed to Test Step 2
Results: There is a problem with the wiring and/or a connector.
Repair: Repair the wiring and/or the connector. Replace parts, if necessary. Ensure that all the seals are properly connected. Verify that the repair eliminates the problem.
2. Check the Switch Circuit at the ECM for Proper Operation
A. Disconnect the P1 connector.
B. Refer to Illustrations 1 and 2. Determine the P1 terminal locations for the suspect switch.
Note: If you are troubleshooting the crank override switch, ensure that the starter motor select switch is positioned to select the left starter.
C. Connect one lead of a multimeter to the P1 terminal for the suspect switch. Connect the other lead of the multimeter to ground. If the starter motor select switch is suspect, check that there is continuity across the terminals at the switch. If necessary, replace the switch
Note: Wiggle the harnesses during the following measurements to reveal any intermittent short condition.
D. Measure the resistance between the P1 terminal for the suspect switch and ground.
E. Activate the switch and measure the resistance again.
Open and short
Results: One resistance measurement indicates an open circuit. The other resistance measurement indicates a short circuit.
Repair: The switch is operating correctly. Operate the engine and check the switch for proper operation.
If the switch does not operate correctly, there may be a short circuit between the circuit for the suspect switch and another circuit. Carefully reinspect the components. Refer to Troubleshooting, "Electrical Connectors - Inspect". Locate the short circuit and perform repairs.
Results: Both resistance measurements indicate an open circuit or both resistance measurements indicate a short circuit.
Repair: There is a problem with the circuit for the switch. The problem could be in the switch, in the wiring, or in a connector.
There is a problem with the circuit for the switch. The problem could be in the switch, in the wiring, or in a connector.
If the inspection does not identify the faulty component, replace the switch and test the switch again.
If the problem is not resolved, repair the wiring or the connector. Replace parts, if necessary. Verify that the problem is resolved.
Table 2
3. If Applicable, Check the Switch Circuit at the Control Assembly for Proper Operation
A. Disconnect the appropriate input connector at the control assembly.
B. Refer to Illustrations 1 and 2. Determine the input connector terminal at the control assembly for the suspect switch.
C. Connect one lead of a multimeter to the terminal for the suspect switch. Connect the other lead of the multimeter to negative ground.
Note: Wiggle the harnesses during the following measurements to reveal any intermittent short condition.
D. Measure the resistance between the P1 terminal for the suspect switch and ground.
E. Activate the switch and measure the resistance again.
Control Assembly
Results: One resistance measurement indicates an open circuit. The other resistance measurement indicates that a short circuit exists.
Repair: The switch is operating correctly. Operate the engine and check the switch for proper operation.
If the switch does not operate correctly, there may be a short circuit between the circuit for the suspect switch and another circuit. Carefully reinspect the components. Refer to Troubleshooting, "Electrical Connectors - Inspect". Locate the short circuit and perform repairs.
Results: Both resistance measurements indicate an open circuit or both resistance measurements indicate a short circuit.
Repair: There is a problem with the circuit for the switch. The problem could be in the switch, in the wiring, or in a connector.
Carefully reinspect the components. Refer to Troubleshooting, "Electrical Connectors - Inspect" for information that relates to troubleshoot