RESISTOR WIRE ELEMENT
- Disconnect and isolate the battery negative cable. The power seat wire harness connectors for the seat cushion and seat back heating elements are secured to a bracket located under the rear edge of the seat cushion frame. Refer to Wiring for complete circuit schematics and connector locations.
- Disconnect the Heated Seat Module (HSM) or Memory Heated Seat Module (MHSM) C2 connector. Check for continuity between the SEAT HEATER B(+) DRIVER circuit cavity of the C2 connector and the seat cushion frame. There should be NO continuity If OK, go to Step 3. If not OK, repair the shorted seat heater B(+) driver circuit as required. NOTE:
WHEN CHECKING HEATED SEAT ELEMENTS FOR CONTINUITY, BE CERTAIN TO MOVE
THE HEATING ELEMENT BEING CHECKED. MOVING THE ELEMENT, SUCH AS SITTING
IN THE SEAT WILL ELIMINATE THE POSSIBILITY OF AN INTERMITTENT OPEN IN
THE ELEMENT WHICH WOULD ONLY BE EVIDENT IF THE ELEMENT WAS MOVED IN A
CERTAIN DIRECTION. FAILURE TO CHECK THE ELEMENT IN VARIOUS POSITIONS
COULD RESULT IN AN INCOMPLETE TEST.
- Check for continuity between the SEAT HEATER B(+) DRIVER
circuit cavity of the C2 connector and the ground circuit cavity. There
should be continuity at all times (even upon moving or sitting in the
seat). If OK, proceed with testing the other components in the heated
seat system. If not OK, replace the open heating element.
are tests that will help to diagnose the components and circuits that
are hard wired inputs or outputs of the heated seat system. However,
these tests may not prove conclusive in the diagnosis of this system.
In order to obtain conclusive testing of the heated seat system, the
Programmable Communications Interface (PCI) data bus network
and all of the electronic modules that provide inputs to, or receive
outputs from the heated seat system components must be checked.
The most reliable, efficient, and accurate means to diagnose the heated
seat system requires the use of a DRB scan tool and the proper
Diagnostic Procedures. The DRB scan tool can provide confirmation that
the PCI data bus is functional, that all of the electronic modules are
sending and receiving the proper messages on the PCI data bus, and that
the Heated Seat Module (HSM) or Memory Heated Seat Module (MHSM)
is receiving the proper hard wired inputs and relaying the proper hard
wired outputs to perform its heated seat system functions.
For complete circuit diagrams, refer to Wiring Diagrams.
NOTE: DO NOT ATTEMPT TO SWAP MEMORY OR NON-MEMORY HEATED SEAT
MODULES FROM ONE VEHICLE TO ANOTHER. MOST OF THESE MODULES ARE VEHICLE
FEATURE SPECIFIC AND THEREFORE NOT INTERCHANGEABLE. ALWAYS USE THE
CORRECT PART NUMBERED MODULE WHEN DIAGNOSING OR REPLACING A MODULE.
WARNING: REFER TO THE RESTRAINTS SECTION BEFORE ATTEMPTING ANY
STEERING WHEEL, STEERING COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. FAILURE TO TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL INJURY.
Before testing the individual components in the heated seat system, check the following:
If the heated seat switch LED indicators do not light with the ignition
switch in the ON position and the heated seat switch in the Low or High
position, check the fused ignition switch output (RUN) fuse in the
junction block. If OK, refer to Heated Seat Switch Diagnosis and
Testing in this section. If not OK, repair the shorted circuit or
component as required and replace the faulty fuse.
If the heated seat switch LED indicators light, but the heating
elements do not heat, check the power seat circuit breaker in the
junction block. If OK, refer to Heated Seat Element Diagnosis and
Testing in this section. If not OK, replace the faulty power seat