Diagnostic Test
- READ AND RECORD DTCS AND ENVIRONMENTAL DATA - ERASE DTCS AND CHECK FOR DTC TO RETURN
- With the scan tool, read DTCs in all Electronic Control Units (ECUs) and record on the repair order.
- With the scan tool, run a vehicle Scan Report, or record the Environmental Data related to the DTCs.
- With the scan tool, erase all DTCs.
- Turn the ignition off for a minimum of 10.0 seconds.
- Start the Engine.
- Turn the Right Front Heated Seat on.
- With the scan tool, read CSWM DTCs.
Is the same DTC active?
Yes
- Go To 2
No
- Perform the appropriate INTERMITTENT CONDITION diagnostic procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION .
- ISOLATE AND LOAD TEST THE (F506) RIGHT FRONT SEAT CUSHION HEATER SUPPLY CIRCUIT TO CHECK FOR AN OPEN OR HIGH RESISTANCE
- The ignition must be off when performing a load test on a circuit.
- Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and every component harness connector containing the circuit being tested.
- Connect the positive lead of the load test tool to the positive side of the Battery (A). Note: Refer to the diagram below.
- Using an approved back probe tool, connect the negative lead of the load test tool to the circuit being tested at the one of the component harness connectors (B).
- Using an approved back probe tool and a fused jumper wire, connect the circuit being tested to the negative side of the Battery or a known good ground at the other component harness connector (C and D).
- The bulb on the load test tool should be illuminated and bright if there is no resistance in the circuit.
NOTE:Note: Why load test a circuit? A load test is used to determine if a circuit is capable of carrying the amperage needed to perform properly. The 3156 bulb in the load tool illustrated, is a simple but effective method of testing circuit functionality. A 3156 Bulb has approximately 6.0 Ohms of resistance when the bulb is powered and draws approximately 2.0 amps of current. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop. Refer to CIRCUIT LOAD TESTING PROCEDURES .
NOTE:Note: A 12-volt test light can be substituted for the load test tool, but only if the test light draws enough current to effectively load test the circuit. Many high impedance test lights draw very little amperage (less than 0.1 amps) and are not reliable to load test a circuit. To perform a proper load test of a circuit, the tool being used should draw more than approximately 0.75 amps.
NOTE:Note: Why perform a Voltage Drop Test? To verify with certainty there is not any resistance in the circuit being tested, perform a simple voltage drop test across the 3156 bulb of the load test tool. To do so perform the following:
- 1. Connect the leads of a DVOM to the alligator clips on the load test tool while the load test tool is connected in series with the circuit.
- 2. Compare the voltage drop across the bulb to the voltage reading across the Battery terminals.
- 3. The voltage dropped across the bulb should be equal to the voltage reading across the Battery terminals if there is no resistance in the circuit being tested.
Example: 2.0 Ohms of resistance in the circuit being tested will cause the voltage measurement across the bulb to be 25% less than when compared to Battery voltage. The reason for this is that the 2.0 Ohms in the circuit makes up 25% of the total circuit resistance of 8.0 Ohms. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop. Refer to CIRCUIT LOAD TESTING PROCEDURES .
WARNING:To avoid possible serious or fatal injury, DO NOT load test any air bag/restraint system components or circuits using the procedures listed here. Refer to the Service Information for proper air bag/restraint system testing procedures.
CAUTION:Do not load test any circuits with components still connected to the circuit.
NOTE:When probing a circuit at an Electronic Control Unit (ECU) harness connector, always use an appropriate back probing tool to prevent any possible damage to the ECU terminals.
NOTE:Compare the brightness of the bulb in the load test tool to that of a direct connection to Battery.
Is the load test bulb illuminated and bright?
Yes
- Go To 3
No
- Repair the (F506) Right Front Seat Cushion Heater Supply circuit for an open or high resistance.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
- CHECK THE (Z917) GROUND CIRCUIT FOR AN OPEN OR HIGH RESISTANCE BY LOAD TESTING THE CIRCUIT
- Disconnect the component harness connector to isolate the ground circuit.
- Connect the positive lead of the load test tool to the positive side of the Battery.
- Connect the negative lead of the load test tool to the ground circuit at the component harness connector (A). Note: refer to the diagram below.
- The bulb on the load test tool should be illuminated and bright if there is no resistance in the circuitry.
NOTE:Note: Why load test a circuit? A load test is used to determine if a circuit is capable of carrying the amperage needed to perform properly. The 3156 bulb in the load tool illustrated, is a simple but effective method of testing circuit functionality. A 3156 Bulb has approximately 6.0 Ohms of resistance when the bulb is powered and draws approximately 2.0 amps of current. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop. Refer to CIRCUIT LOAD TESTING PROCEDURES .
NOTE:Note: A 12-volt test light can be substituted for the load test tool, but only if the test light draws enough current to effectively load test the circuit. Many high impedance test lights draw very little amperage (less than 0.1 amps) and are not reliable to load test a circuit. To perform a proper load test of a circuit, the tool being used should draw more than approximately 0.75 amps.
NOTE:Note: Why perform a Voltage Drop Test: To verify with certainty there is not any resistance in the circuit being tested, perform a simple voltage drop test across the 3156 bulb of the load test tool. To do so perform the following:
- 1. Connect the leads of a DVOM to the alligator clips on the load test tool while the load test tool is connected in series with the circuit.
- 2. Compare the voltage drop across the bulb to the voltage reading across the Battery terminals.
- 3. The voltage dropped across the bulb should be equal to the voltage reading across the Battery terminals if there is no resistance in the circuit being tested.
Example: 2.0 Ohms of resistance in the circuit being tested will cause the voltage measurement across the bulb to be 25% less than when compared to Battery voltage. The reason for this is that the 2.0 Ohms in the circuit makes up 25% of the total circuit resistance of 8.0 Ohms. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop. Refer to CIRCUIT LOAD TESTING PROCEDURES .
NOTE:When probing a circuit at an Electronic Control Unit (ECU) harness connector, always use an appropriate back probing tool to prevent any possible damage to the ECU terminals.
NOTE:Compare the brightness of the bulb in the load test tool to that of a direct connection to Battery.
Is the load test bulb illuminated and bright?
Yes
- Go To 4
No
- Repair the (Z917) Ground circuit for an open or high resistance.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
- CHECK THE RIGHT FRONT SEAT CUSHION HEATER ELEMENT RESISTANCE
- Measure the resistance of the Right Front Seat Cushion Heater element between the (F506) Right Front Seat Cushion Heater Supply circuit and the (Z917) Ground circuit at the Right Seat Cushion Heater component connector.
NOTE:When probing a circuit always use an appropriate back probing tool to prevent any possible damage to the terminals.
Is the resistance between 2.26 Ohms and 3.38 Ohms at 20°C (68°F)?
Yes
- Go To 5
No
- Replace the Right Front Seat Cushion Heater element in accordance with the Service Information. Refer to PAD, HEATER, CUSHION, REMOVAL AND INSTALLATION .
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
- CHECK RELATED HARNESS CONNECTIONS
- Disconnect all CSWM harness connectors.
- Disconnect all related in-line harness connections (if equipped).
- Disconnect the related component harness connectors.
- Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
- Proper connector installation.
- Damaged connector locks.
- Corrosion.
- Other signs of water intrusion.
- Weather seal damage (if equipped).
- Bent terminals.
- Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
- Terminals that have been pushed back into the connector cavity.
- Check for spread terminals and verify proper terminal tension.
Repair any conditions that are found.
- Connect all CSWM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
- Connect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
- Connect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
- With the scan tool, erase DTCs.
- Test drive or operate the vehicle in accordance with the when monitored and set conditions.
- With the scan tool, read CSWM DTCs.
Is the same DTC active?
Yes
- Replace the Comfort Seat Wheel Module (CSWM) in accordance with the Service Information. Refer to MODULE, COMFORT SEAT AND WHEEL (CSWM), REMOVAL AND INSTALLATION .
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
No
- Repairing the wiring harness or connections corrected the problem.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .