The flashing indicates a fault code. Here's some info on the XJ's seat heaters:
DIAGNOSIS AND TESTING - HEATED SEAT SYSTEM
Refer toWiring Diagrams for the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, further details on wire harness routing and retention, as well as pin-out and location views for the various wire harness connectors, splices and grounds.
NOTE: DO NOT ATTEMPT TO SWAP 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.
HEATED SEAT SYSTEM DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
NO HEATED SEAT SWITCH ILLUMINATION WITH IGNITION ON 1. Faulty fuse. 1. Check heated seat fuse in Junction Block (JB). Replace fuse, if required.
2. Wiring faulty. 2. Check fused ignition switch output (run-acc) circuit from heated seat switch connector to ignition switch. Repair, if required.
3. Ground faulty. 3. Check for ground at heated seat switch connector. Repair, if required.
4. Faulty switch. 4. Refer to Heated Seat Switch for the proper switch diagnosis and testing procedures.
SEATS HEAT, BUT NO HEATED SEAT SWITCH INDICATORS 1. Wiring faulty. 1. Check LED driver circuit(s) from heated seat switch connecvtor to heated seat module connector. Repair, if required.
2. Faulty switch LED. 2. Replace switch with known good unit. If OK, discard faulty switch.
3. Faulty module. 3. Refer to Heated Seat Module for the proper module diagnosis and testing procedures. Replace, if required.
SEATS DO NOT HEAT AND NO HEATED SEAT SWITCH INDICATORS 1. Faulty circuit breaker. 1. Check power seat circuit breaker in Junction Block (JB). Replace, if required.
2. Faulty relay. 2. Refer to Heated Seat Relay for the proper relay diagnosis and testing procedures. Replace, if required.
3. Faulty module. 3. Refer to Heated Seat Module for the proper module diagnosis and testing procedures. Replace, if required.
HEATED SEAT SWITCH INDICATORS FLASHING 1. Faulty sensor. 1. Refer to Heated Seat Sensor for the proper heated seat system self-diagnostic routine. Repair, as required.
2. Faulty element. 2. Refer to Heated Seat Element for the proper heated seat system self-diagnostic routine. Repair, as required.
SELF-DIAGNOSTICS - HEATED SEAT SYSTEM
The heated seat system is capable of performing some self-diagnostics. The following table depicts the various failure modes which will be reported to the occupant via flashing of the heated seat switch Light-Emitting Diode (LED) indicators. Flashing LED indicators on the driver side switch indicate that a fault exists in the driver side portion of the system and, likewise, flashing LED indicators on the passenger side switch indicate a fault exists in the passenger side portion of the system. The LED indicators will flash at a rate of approximately one-half second on, and one-half second off for a duration of one minute. This process will repeat each time an attempt is made to turn the system on with the heated seat switches until the problem has been corrected.
HEATED SEAT SYSTEM SELF-DIAGNOSTIC TABLE
FAILURE MODE SWITCH "HI" LED INDICATOR SWITCH "LO" LED INDICATOR
Shorted Heating Element Flashing Flashing
Open Heating Element Flashing Off
NTC Sensor Value Out of Range Off Flashing
