Jeep 1997 Grand Cherokee Service Manual page 541

ZG
DIAGNOSIS AND TESTING (Continued)
case, there should be no continuity. If OK, go to Step
6. If not OK, replace the faulty inboard switch pod.
(6) Move both heated seat switches to the Low
position. Using an ohmmeter, check the resistance
between the fused ignition switch output circuit ter-
minal and the driver heated seat switch output cir-
cuit terminal in the 10-way connector receptacle on
the back of the inboard switch pod. Repeat this check
between the fused ignition switch output circuit ter-
minal and the passenger heated seat switch output
circuit terminal. In each case, the resistance reading
should be about 11.5 kilohms. If OK, go to Step 7. If
not OK, replace the faulty inboard switch pod.
(7) Move both heated seat switches to the High
position. Using an ohmmeter, check the resistance
between the fused ignition switch output circuit ter-
minal and the driver heated seat switch output cir-
cuit terminal in the 10-way connector receptacle on
the back of the inboard switch pod. Repeat this check
between the fused ignition switch output circuit ter-
minal and the passenger heated seat switch output
circuit terminal. In each case, the resistance reading
should be about 6.5 kilohms. If not OK, replace the
faulty inboard switch pod.
HEATED SEAT CONTROL MODULE
Before testing the heated seat control module, test
the heated seat switch, the heated seat elements, and
the heated seat sensor as described in this group. If
testing of the heated seat switch, elements, and sen-
sor reveals no problems, replace the heated seat con-
trol module with a known good unit and test the
operation of the heated seats. If OK, discard the
faulty heated seat control module. If not OK, test the
circuits from the heated seat switch, elements, and
sensor to the heated seat control module. Repair any
short or open circuits as required. For circuit descrip-
tions and diagrams, refer to 8W-63 - Power Seat
With Heated Seats in Group 8W - Wiring Diagrams.
HEATED SEAT ELEMENT
The wire harness connectors for the seat cushion
and seat back heating elements are located under the
seat, near the rear edge of the seat cushion frame.
For circuit descriptions and diagrams, refer to 8W-63
- Power Seat With Heated Seats in Group 8W - Wir-
ing Diagrams.
SEAT CUSHION
(1) Disconnect and isolate the battery negative
cable. Unplug the 4-way heated seat cushion wire
harness connector.
(2) Check for continuity between the two heated
seat driver circuit cavities of the seat cover half of
the heated seat cushion wire harness connector.
There should be continuity. If OK, go to Step 3. If not
OK, replace the faulty seat cushion cover.
ELECTRICALLY HEATED SYSTEMS
(3) Check for continuity between one of the heated
seat driver circuit cavities of the seat cover half of
the heated seat cushion wire harness connector and
the seat cushion frame. There should be no continu-
ity. If OK, test the seat back element. If not OK,
replace the faulty seat cushion cover.
SEAT BACK
(1) Disconnect and isolate the battery negative
cable. Unplug the 2-way heated seat back wire har-
ness connector.
(2) Check for continuity between the heated seat
driver circuit cavity and the ground circuit cavity of
the seat cover half of the heated seat back wire har-
ness connector. There should be continuity. If OK, go
to Step 3. If not OK, replace the faulty seat back
cover.
(3) Check for continuity between the heated seat
driver circuit cavity of the seat cover half of the
heated seat back wire harness connector and the seat
back frame. There should be no continuity. If OK,
test the heated seat sensor as described in this
group. If not OK, replace the faulty seat back cover.
HEATED SEAT SENSOR
The wire harness connector for the seat cushion
heating element and sensor are located under the
seat, near the rear edge of the seat cushion frame.
For circuit descriptions and diagrams, refer to 8W-63
- Power Seat With Heated Seats in Group 8W - Wir-
ing Diagrams.
(1) Disconnect and isolate the battery negative
cable. Unplug the 4-way heated seat cushion wire
harness connector.
(2) Using an ohmmeter, check the resistance
between the heated seat switch output circuit cavity
and the ground circuit cavity of the seat cover half of
the heated seat cushion wire harness connector. The
sensor resistance should be between 2 kilohms and
200 kilohms. If OK, test the heated seat control mod-
ule as described in this group. If not OK, replace the
faulty seat cushion cover.
REMOVAL AND INSTALLATION
HEATED SEAT SWITCH
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO
RESTRAINT SYSTEMS
STEERING WHEEL,
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
GROUP 8M - PASSIVE
BEFORE ATTEMPTING
STEERING COLUMN,
8N - 9
OR