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Power and heated seats
Power seats Heated seats Upgrading


WJ seats




Power seats

Driver and passenger power front seats were an available factory-installed option for WJ Grand Cherokees. Several different power seat options were offered depending upon the model and year.

The power seat system included the following components:

  • Power lumbar adjuster (ten-way power seat only)
  • Power lumbar switch (ten-way power seat only)
  • Power seat recliner (ten-way power seat only)
  • Power seat switch
  • Power seat track


1999-2001 model seats

Six-way power seat - This power seat is an available option on Laredo models equipped with cloth-trimmed seats and includes a six-way adjustable seat cushion track with manual seat back recliners.

Ten-way power seat - Ten-way power seat - This power seat option was standard on Limited models and optional on Laredo models with leather-trimmed seats. The option included a six-way adjustable seat cushion track plus power seat back recliners plus power lumbar supports, for a "10-way" total. This power seat was also available with the heated seats option on both Laredo and Limited models. Exclusive to Limited models there is a standard equipment memory system that automatically positions the power seat adjustments for two different drivers.


2002-2004 model seats

Six-way power drivers seat with manual passenger seat - This power seat package is an option on Laredo models equipped with cloth trimmed seats and includes a six-way adjustable driver seat track with manual seat back recliners.

Six-way power driver and passenger seat - This power seat package is an option on Laredo models equipped with cloth or leather-trimmed seats and includes six-way adjustable seat tracks with manual seat back recliners. Heated Seats are available on leather-trimmed seats.

Ten-way power drivers seat with Memory and Six-way power passenger seat - This power seat package is standard on Limited models. This option includes a six-way adjustable seat track with power seat back recliners and power lumbar supports for the driver and six-way only for the passenger.

Ten-way power drivers and passenger seats with Memory - This power seat option is standard on Overland models and optional on Limited models. This option includes a six-way adjustable seat cushion track with power seat back recliners and power lumbar supports. Heated Seats are standard with this option.





Heated seats

Individually controlled driver and passenger side electrically heated front seats were available as a factory installed option when also equipped with the power seat option. The heated seat system allows both the driver and the front seat passenger the option to select one of two seat heating ranges, Low or High, or to turn the individual seat heaters Off using the heated seat switches located in the center lower bezel near the bottom of the instrument panel center stack.

The heated seat switch circuit operates on ignition switched battery current supplied through a fuse in the junction block, only when the ignition switch is in the On position.

The heated seat system consists of the following components :

  • Heated seat elements
  • Heated seat sensors
  • Heated seat module (or memory heated seat module)
  • Heated seat switches




Heated seat switches
          
Heated seat switches

Heated seat switches in a 1999 Limited and Heated switch detail


Heated seat switches

The heated seat switches are mounted in the instrument panel center lower bezel, which is located near the bottom of the instrument panel center stack. The two three-position rocker-type switches, one switch for each front seat, provide a resistor multiplexed signal to the Body Control Module (BCM) through separate hard wired circuits.

Each switch has an Off, Low, and High position so that both the driver and the front seat passenger can select a preferred seat heating mode. Each switch has two Light-Emitting Diodes (LED), one each for the Low position and the High position, which light to indicate that the heater for the seat that the switch controls is turned on. Each switch is also back lit by a replaceable incandescent bulb.

The heated seat switches and their LEDs cannot be repaired. If either switch or LED is faulty or damaged, the entire switch unit must be replaced. The incandescent switch illumination bulb and bulb holder units are available for service replacement.

The heated seat system also relies upon resources shared with other electronic modules in the vehicle over the Programmable Communications Interface (PCI) data bus network. The PCI data bus network allows the sharing of sensor information. This helps to reduce wire harness complexity, internal controller hardware, and component sensor current loads.


Heated seat operation

There are three positions that can be selected with each of the heated seat switches: Off, Low, or High. When the top of the switch rocker is fully depressed, the High position is selected and the high position LED indicator illuminates. When the bottom of the switch rocker is fully depressed, the Low position is selected and the low position LED indicator illuminates. When the switch rocker is moved to its neutral position, Off is selected and both LED indicators are extinguished.

Both switches provide separate resistor multiplexed hard wire inputs to the BCM to indicate the selected switch position. The BCM monitors the switch inputs and sends heated seat switch status messages to the Heated Seat Module (HSM) or the Memory Heated Seat Module (MHSM) over the Programmable Communications Interface (PCI) data bus. The HSM or MHSM responds to the heated seat switch status messages by controlling the output to the seat heater elements of the selected seat. The Low heat position set point is about 97° F (36° C), and the High heat position set point is about 105° F (41° C).




Upgrading to power or power/heated seats (Laredo models)

Power or power/heated seats can be added to most WJ's that came with standard seats. The entire seat assemblies will have to be exchanged. All seats use the same bolt pattern so the installation fit will always be exact. For power seat wiring, all that is required is a constant +12V wire and a Ground wire. Vehicles that came without power seats are not pre-wired. For the Ground wire it is probably best to run it over to the center console area where it can be attached to a metal bracket. Do not drill a hole in the floor below the seat. For the power lead, run a wire with an in-line fuse up to the fuse panel area where you can find a + wire to tap into.


Power / heated seats (leather only)

For 1999-2004 Grand Cherokees that came without heated seats the wiring is a little more involved as the heat function is controlled via the PCI Bus and you will be hooking up two seats. Two heated seat switches will have to be purchased and installed in the center bezel. Some center bezels have the holes pre-cut with blank plates installed while others may have to be trimmed out with a dremel type tool. Some owners elect to just purchase a new center console bezel assembly as there are several choices available (with and without ashtray for example). See Interior Trim for a list of part numbers for center bezels.

NOTE: A factory pre-wired harness for the heated seat switches is located behind the center lower bezel in most if not all models that did not have this feature. All you have to do is plug the two harness plugs into the two heated seat switches.


Power / heated seat wiring at the seat location

For the driver's seat, Pin 4 (red) is the 12V lead and Pin 5 (black) is the Ground.

On the Passenger seat Pin 3 (Red/LB) is the 12V lead and Pin 2 (black) is the Ground.

The Ground wires for the two seats should be run together to one Ground location. The power wires for both seats can be hooked together and a single wire with an in-line fuse run to the front fuse box area.

The PCI Bus wire is run from the drivers seat to a location under the dash where you can tap into any PCI wire. Most owners have just tapped into the Bus at the radio harness. On 1999-2001 WJ's, a single separate PCI wire plugs into the back of the radio. For 2002-2004 models tap in to Pin 14 of the 22-pin radio harness. Radio wiring diagrams can be found Here .

In addition to the PCI Bus, Power and Ground, four wires must be run between the drivers seat and the passenger seat, as shown in the table below:


Grand Cherokee WJ - Power / Heated Seat upgrade wiring
DRIVER SEATTOPASSENGER SEATTOPCI / Power / Ground
Pin 3 (YL/VT)(not required)PCI Bus
Pin 4 (RED)Pin 3 (Red/LB)12V fused Power
Pin 5 (BLK)Pin 2 (BLK)Ground
Pin 1 (PK/BK)Pin 4 (PK/BK) 
Pin 2 (DG/WT)Pin 1 (DG/WT)
Pin 6 (BR/WT)Pin 5 (BR/WT)
Pin 8 (BK/VT)Pin 6 (BK/VT)



seat pinouts

Wiring pinouts for the power / heated seat connectors




Heated seat troubleshooting


TSB #0800401B - HEATED SEAT INOPERATIVE

Date: 12/20/01 (supersedes 0800401A dated 03/01)

Model Year(s): 1999-2004

Description: Heated seat inoperative. On some vehicles the heated seat may be inoperative due to an open circuit in the seat cushion heating element.

Details: This bulletin involves installing a kit to repair an open circuit in the heated seat heating element circuit. Using a digital ohmmeter, check the resistance across the four way heated seat feed connector under the seat. The resistance between terminals “A” and “B” should be 0.90 ohms to 1.90 ohms. If the resistance value falls outside of this range, perform the Repair Procedure.

NOTE: SOME VEHICLES USE CARBON FIBER HEATING ELEMENTS. CARBON FIBER HEATING ELEMENTS HAVE A RESISTANCE OF 10 TO 14 OHMS IN THE BOLSTER ELEMENT. SEATS WITH CARBON FIBER ELEMENTS HAVE TWO CONNECTORS AT THE BACK OF THE SEAT. A TWO WAY CONNECTOR AND A FOUR WAY CONNECTOR. CARBON FIBER HEATING ELEMENTS ARE NOT SERVICEABLE AND REQUIRE REPLACEMENT OF THE SEAT COVER.

Parts required:

P/N 5019769AA - Heated Seat Repair Kit (For cushion only, one kit per heating element, two per cushion. MSRP: $20.75)

P/N 68002999AB (superseded from P/N 5072485AA) - "Peel & stick" Heating Element kit - Seat back (2001-up Vehicles, see Notes below. MSRP: $235.00)

P/N 68002999AB (superseded from P/N 5072486AB) - "Peel & stick" Heating Element kit - Seat cushion (2001-up Vehicles, see Notes below. MSRP $235.00)

P/N 5000032AA - "Peel & stick" Heating Element - Seat back, (2003-2004 vehicles built after September 10, 2002. MSRP $90.85)

P/N 68002999AA (superseded from P/N 5000031AA) - "Peel & stick" Heating Element kit - Seat cushion, (2003-2004 vehicles built after September 10, 2002. MSRP $235.00)

The heated seat repair kit, 05019769AA contains detailed installation instructions. Follow the instructions provided in the kit for installation. Refer to the 2002 Grand Cherokee service manual, publication number 81–370–02064, page 8G-14, for instructions on the replaceable heating elements, P/N 5072485AA and 5072486AA).

NOTES:

1999 Trim code DL: Use 5019769AA on vehicles built before Nov. 17, 1998. For 1999 model year vehicles built after Nov. 17, 1998 - replace seat cover.

2000 Trim code DL: Replace seat cover

2001 Trim code EL: Use 5019769AA for vehicles built before Sept. 18, 2000. Vehicles built after Sept. 18, 2000 - use replaceable heating elements - 5072485AA (seat back), 5072486AB (seat cushion).

2001 Trim code FL: Replace seat cushion for vehicles built before Sept. 18, 2000.

2001-2003: For vehicles built after Sept. 18, 2000 and up to September 10, 2002 use replaceable ("peel and stick") heating elements 5072485AA (seat back, MSRP $30.85) or 5072486AA (seat cushion, MSRP $46.50).

2003-2004: Vehicles built after September 10, 2002 use replaceable ("peel and stick") heating elements 5000032AA (seat back, MSRP $97.00) and 5000031AA (seat cushion, MSRP $138.00).



Special thanks to Marcel Müller for providing information from his seat upgrade project.



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