Seat Temperature Element: Testing and Inspection
Inspection and Verification
1 Verify the customer concern.
2 Visually inspect for obvious signs of mechanical or electrical damage.
3 If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
4 If the cause is not visually evident, check for Diagnostic Trouble Codes (DTC's) and refer to the DTC Index.
NOTE:
If the control module or a component is suspect and the vehicle remains under manufacturer warranty, refer to the warranty policy and procedures manual (section B1.2), or determine if any prior approval programme is in operation, prior to the installation of a new module/component.
NOTE:
Generic scan tools may not read the codes listed, or may read only five digit codes. Match the five digits from the scan tool to the first five digits of the seven digit code listed to identify the fault (the last two digits give additional information read by the manufacturer approved diagnostic system).
NOTE:
When performing electrical voltage or resistance tests, always use a digital multimeter (DMM) accurate to three decimal places, and with an up-to-date calibration certificate. When testing resistance, always take the resistance of the DMM leads into account.
NOTE:
Check and rectify basic faults before beginning diagnostic routines involving pinpoint tests.
NOTE:
Inspect connectors for signs of water ingress, and pins for damage and/or corrosion.
NOTE:
If DTCs are recorded and, after performing the pinpoint tests, a fault is not present, an intermittent concern may be the cause. Always check for loose connections and corroded terminals.
NOTE:
CAUTION: When probing connectors to take measurements in the course of the pinpoint tests, use the adaptor kit, part number 3548-1358-00.
DTC Index
For a complete list of all diagnostic trouble codes that could be logged on this vehicle, please refer to Vehicle / A L L Diagnostic Trouble Codes ( DTC ).
NOTE:
To ensure an accurate resistance reading, calibrated test equipment must be used
PINPOINT TEST G1447597p1 : Seat Heater Mat
G1447597t7 : Check for DTC's
1 Where possible use the manufacturer approved diagnostic system to review any logged seat heater mat DTC's
- Were any seat heater mat DTC's logged?
->Yes
Carry out the help text action for any logged DTC's. Clear the DTC and retest. If DTC's return follow the tests listed below
GO to Pinpoint Test G1447597t1.
->No
GO to Pinpoint Test G1447597t1.
G1447597t1 : Manual Check
NOTE:
The manual check should be carried out by someone familiar with correct seat heat operation
NOTE:
On full power the seat should be hot to touch
1 If required operate the vehicle air conditioning on full for 10 minutes to reduce the in vehicle ambient temperature
2 Operate the seat heater on full power
- Does the seat heater operate correctly?
->Yes
Clear any stored DTC's and retest. If seat heater operation is correct no further action required
->No
GO to Pinpoint Test G1447597t2.
G1447597t2 : Short Circuit To Ground
1 Refer to the electrical circuit diagrams and the seat heater mat application chart (see above) to identify the connector
2 Disconnect the connector
3 Refer to the electrical circuit diagrams and check the seat heater mat heater circuit and theNTC resistor circuit for short circuit to ground
- Are either of the circuits short circuit to ground?
->Yes
Repair the circuit or replace the seat heater mat as required. Refer to the warranty policy and procedures manual, or determine if any prior approval programme is in operation, prior to the installation of a new module/component. Clear any stored DTC's and retest
->No
GO to Pinpoint Test G1447597t3.
G1447597t3 : Circuit Continuity Test
1 Refer to the electrical circuit diagrams and check the seat heater mat ( heater circuit ) for circuit continuity
- Does the seat heater mat heater circuit pass the continuity test?
->Yes
GO to Pinpoint Test G1447597t4.
->No
Repair the circuit or replace the seat heater mat as required. Refer to the warranty policy and procedures manual, or determine if any prior approval programme is in operation, prior to the installation of a new module/component. Clear any stored DTC's and retest
G1447597t4 : Power Consumption
NOTE:
The seat heater power supply cycles on and off dependant on the seat and cabin temperature and may only switch on for 5 seconds in 30 seconds
1 Reconnect the connector
2 Operate the vehicle air conditioning on full for 10 minutes to reduce the in vehicle ambient temperature
3 Refer to the electrical circuit diagrams and check the seat heater mat ( heater circuit ) using a current clamp
4 Operate the seat heater on full power
5 Use the chart above to calculate typical value (V/R=I) (Voltsdivided by Resistanceequals Current in Amps)
6 Examples (12 volts / 0.5 ohms =24 amps) (12 volts / 1 ohms = 12 amps) (12 volts / 2 ohms = 6 amps)
- Does the seat heater mat consume the correct level of current?
->Yes
Clear any stored DTC's and retest. If operation correct, no further action required
->No
GO to Pinpoint Test G1447597t5.
G1447597t5 : Resistance Check
NOTE:
Ensure the multimeter used is calibrated and a resistance reading of0ohms is shown when the test leads are connected together, alternately subtract any resistance shown from the result
NOTE:
The seat heater mat circuits should be checked at the seat heater module connector
NOTE:
Refer to the electrical circuit diagrams and to confirm the total resistance of the circuit the cushion and backrest are connected in series
1 Refer to the electrical circuit diagrams and the seat heater mat application chart (see above) to identify the terminals
2 Disconnect the connector
3 Using a multimeter, carry out a resistance check of the seat heater mat heater circuit and theNTC resistor circuit. Record the results
4 Compare the results to the chart (see above)
- Are the results within specification at the given ambient temperature? (tolerance +/-0.5Ohms)
->Yes
Reconnect the connector. Clear any stored DTC's and retest. If customer concern or DTC's return refer to electrical circuit diagrams and investigate the power and ground supply circuits
->No
Replace the seat heater mat as required. Refer to the warranty policy and procedures manual, or determine if any prior approval programme is in operation, prior to the installation of a new module/component. Clear any stored DTC's and retest