2014 Jeep Wrangler JK Factory Service Manual 08 - Electrical

MODULE, Heated Seat

DESCRIPTION

The Heated Seat Module (HSM) (1) is mounted to the instrument panel support, next to the radio. The HSM has an integral electrical connector (2) and is secured to the instrument panel support by a plastic alignment tab and push-pin retainer.

The HSM is a microprocessor designed to use the Local Interface Network (LIN) data bus messages from the instrument cluster, also referred to as the Cab Compartment Node (CCN). The CCN receives inputs from the heated seat switches and in turn, signals the HSM to operate the heated seat elements for both front seats.

OPERATION

The Heated Seat Module (HSM) operates on fused battery current received from the ignition switch. The HSM is grounded to the body at all times through the electrical connector. Inputs to the HSM include Local Interface Network (LIN) data bus messages and standard hard-wired 12 volt power and ground. In response to the LIN inputs the HSM will control the battery current to the appropriate heated seat elements.

When a heated seat switch LIN data bus signal is received by the HSM, the module energizes the selected heated seat element. The Low heat set point is about 38° C (100.4° F), and the High heat set point is about 42° C (107.6° F).

In addition to operating the heated seat elements, the HSM sends LED illumination messages to the instrument cluster, sometimes referred to as the Cab Compartment Node (CCN) over the LIN data bus. The CCN then sends the LED illumination message to the accessory switch bank so that the appropriate LEDs are illuminated for any given heating level. Pressing the switch once will select high-level heating. Pressing the switch a second time will select low-level heating. Pressing the switch a third time will shut the heating elements off.

The heated seat control system is diagnosed using a scan tool (Refer to 28 - DTC-Based Diagnostics/NODE, Cabin Compartment (CCN) - Diagnosis and Testing).

REMOVAL

WARNING:

Disable the airbag system before attempting any steering wheel, steering column, or instrument panel component diagnosis or service. Disconnect and isolate the negative battery (ground) cable. Wait two minutes for the airbag system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the airbag system. Failure to follow these instructions may result in possible serious or fatal injury.

CAUTION:

Use care when removing the Heated Seat Module (HSM) from the seat to prevent damage to the plastic HSM housing and retainer. Failure to follow these instructions may result in damage to the HSM and retainer.


  1. Disconnect and isolate the negative battery cable.

    2.  
  2. Remove the radio (Refer to 08 - Electrical/8A - Audio and Video/RADIO - Removal) .

    3.  
  3. Using an appropriate door trim tool or needle nose pliers, disengage the tab and push-pin retainer that secures the Heated Seat Module (HSM) (1) to the instrument panel support (2).

    4.  
  4. Disconnect the wire harness connector (3) from the HSM.

    5.  
  5. Remove the HSM from the instrument panel.
    .

    6.  

INSTALLATION

CAUTION:

Properly align the tab and retainer for the Heated Seat Module (HSM) to the holes in the instrument panel support, prior to engagement. Failure to follow these instructions may result in damage to the HSM tab and retainer.


  1. Position the Heated Seat Module (HSM) (1) to the instrument panel and connect the wire harness connector (3).

    2.  
  2. Align the tab and push-pin retainer to the holes in the instrument panel support (2) and fully engage the retainer to the support.

    3.  
  3. Install the radio (Refer to 08 - Electrical/8A - Audio and Video/RADIO - Installation) .

    4.  
  4. Reconnect the negative battery cable.

    5.  
  5. Verify proper heated seat system operation.

    6.