Operation; Diagnosis And Testing - Heated Seat Element; Removal; Installation - Chrysler PT Cruiser Service & Repair Manual

8G - 6

HEATED SEAT SYSTEM

HEATED SEAT ELEMENT (Continued)

OPERATION

The heated seat elements resist the flow of electri-
cal current. When battery current is passed through
the elements, the energy lost by the resistance of the
elements is released in the form of heat. The temper-
ature sensor is a NTC thermistor. The heated seat
module supplies a five-volt current to one side of
each sensor, and monitors the voltage drop through
the sensor on a return circuit. When the temperature
of the seat cushion cover rises, the resistance of the
sensor decreases. The heated seat module uses this
temperature sensor input to monitor the temperature
of the seat, and regulates the current flow to the seat
heating elements accordingly.
DIAGNOSIS AND TESTING - HEATED SEAT
ELEMENT
For complete circuit diagrams, refer to Wiring
Diagrams.
NOTE: When checking heated seat elements for
continuity, be certain to move the heating element
being checked. Moving the element, such as sitting
in the seat will eliminate the possibility of an inter-
mittent open in the element which would only be
evident if the element was in a certain position.
Failure to check the element in various positions
could result in an incomplete test.
(1) Disconnect and isolate the battery negative
cable. Disconnect the heated seat module wire har-
ness connector. Check for continuity between the seat
heater B+ driver circuit cavity and a good ground,
preferably under the seat. There should be continu-
ity, less than 7 ohms. If OK, go to Step 2. If not OK,
replace the heating element assembly.
(2) Check for continuity between the seat heater
B+ driver circuit cavity and the seat back frame.
There should be no continuity. If OK, go to Diagnosis
and Testing the heated Seat Module in the electronic
control modules section of this service manual for
additional diagnostics. If not OK, replace the element
as required.

REMOVAL

Do not attempt to remove the heating element
from the seat or seat back cushion. The original ele-
ment is permanently attached to the seat cushions
and cannot be removed without damaging the cush-
ion. The service replacement (if available) heating
elements are designed to be applied directly over the
original seat heating elements.
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the appropriate seat cushion or seat
back trim cover. Refer to the Body section of the ser-
vice manual for the procedures.
(3) Disconnect the inoperative heated seat cushion
or seat back element electrical connectors.
(4) Locate the wires leading from the inoperative
heating element and cut them off flush with the edge
of the original heating element.

INSTALLATION

(1) Peel off the adhesive backing on the back of the
replacement heating element and stick directly over
the original heating element (Fig. 5).
CAUTION: During the installation of the replace-
ment heating element, be careful not to fold or
crease the element assembly. Folds or creases will
cause premature failure.
Fig. 5 HEATING ELEMENT INSTALLATION
1 - ORIGINAL (INOPERATIVE) HEATING ELEMENT
2 - REPLACEMENT HEATING ELEMENT
(2) Connect the new heating element electrical
connectors (Fig. 6).
(3) Connect the negative battery cable.
(4) Verify heated seat system operation.
(5) Install the appropriate seat cushion or seat
back trim cover. Make certain the seat wire harness
is correctly routed through the seat and seat back.
The excess wire between the cushion and back ele-
ments should be securely tucked between the rear of
the cushion foam and the rear carpet flap of the trim
cover.
PT