There was a recall for the heated seats on the '02 models. >http://www.wjjeeps.com/recall.htm#2002
Also read this:
TSB #0800401B - HEATED SEAT INOPERATIVE Date:
12/20/01 (supersedes 0800401A dated 03/01)
Heated seat inoperative. On some vehicles the heated seat may be inoperative due to an open circuit in the seat cushion heating element.
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.
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P/N 68002999AB (superseded from P/N 5072485AA) - "Peel & stick" Heating Element kit - Seat back (2001-up Vehicles, see Notes below.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P/N 68002999AB (superseded from P/N 5072486AB) - "Peel & stick" Heating Element kit - Seat cushion (2001-up Vehicles, see Notes below.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P/N 68002999AA (superseded from P/N 5000031AA) - "Peel & stick" Heating Element kit - Seat cushion, (2003-2004 vehicles built after September 10, 2002.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).
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).