Seat Heating System and Seat Cooling System — Cadillac ATS I (2012-2014)

Scheme 80

Scheme 80: Power, Grounds, Serial Data and Controls (KA1)

Scheme 81

Scheme 81: Front Seat Heating (KA1)

Diagnostic Code Index

DTC	Description
DTC B191A	DTC B191A 39 Front Heated Seat Module

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage
B+ Terminal 2 X2	4, 5	4, 5
B+ Terminal 3 X2	U1524 00, 1	U1524 00, 1
Driver Heated Seat Back Element Control	B191A 39, 2	2	6
Driver Heated Seat Back Element Ground		2
Driver Heated Seat Cushion Element Control	B191A 39, 3	3	6
Driver Heated Seat Cushion Element Ground		3
Passenger Heated Seat Back Element Control	B191A 39, 4	4	6
Passenger Heated Seat Back Element Ground		4
Passenger Heated Seat Cushion Element Control	B191A 39, 5	5	6
Passenger Heated Seat Cushion Element Ground		5
Ground		1
1. The driver and front passenger heated seats are inoperative. 2. The driver seat back heat function is inoperative 3. The driver seat cushion heat function is inoperative 4. Front passenger seat back heat function is inoperative 5. Front passenger seat cushion heat function is inoperative 6. Heated seat is always ON.

Circuit/System Description

An internal fault is detection inside the control module. No external circuits are involved.

Conditions for Running the DTC

Ignition ON.

Conditions for Setting the DTC

The control module detects an internal fault.

Action Taken When the DTC Sets

The seat heating control module will disable all heated seat functions.

Conditions for Clearing the DTC

The DTC clears when the diagnostic runs and passes.
The history DTC will clear after 40 consecutive fault-free ignition cycles have occurred.

Reference Information

Schematic Reference

Heated/Cooled Seat Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Heated Seats Description and Operation

Electrical Information Reference

«Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

Ignition OFF, disconnect the X2 harness connector at the K29F Seat Heating Control Module - Front.
Connect a 5 A fused jumper wire between each control circuit terminal listed below and B+, one at a time. Driver seat cushion terminal 4 Driver seat back terminal 8 Passenger seat cushion terminal 5 Passenger seat back terminal 6
Verify the fuse does not open between each test. If the fuse opens Repair the short to ground on the circuit. If the fuse does not open
Replace the K29F Seat Heating Control Module - Front.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for K29F Seat Heating Control Module - Front replacement, programming and setup

Symptoms - Seat Heating and Cooling

IMPORTANT

The following steps must be completed before using the symptom tables.

Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) before using the symptom tables in order to verify that all of the following are true: There are no DTCs set. The control module(s) can communicate via the serial data link.
Refer to the «Heated Seats Description and Operation»(/cadillac/ats/i-2012-2014/remont/seats/#seat-heating-system-and-seat-cooling-system) in order to familiarize yourself with the system functions

Visual/Physical Inspection

Inspect for aftermarket devices which could affect the operation of the power seats. Refer to «Checking Aftermarket Accessories»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__checking-aftermarket-accessories) .
Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
Inspect the seat adjuster track for conditions which may cause binding or objects within the seat adjustment range which obstruct movement or interfere with wiring.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Symptom List

Refer to the Front Heated Seat Malfunction diagnostic procedure in order to diagnose the symptom

Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage
B+ Terminal 2 X2	4, 5	4, 5
B+ Terminal 3 X2	U1524 00, 1	U1524 00, 1
Driver Heated Seat Back Element Control	B191A 39, 2	2	6
Driver Heated Seat Back Element Ground		2
Driver Heated Seat Cushion Element Control	B191A 39, 3	3	6
Driver Heated Seat Cushion Element Ground		3
Passenger Heated Seat Back Element Control	B191A 39, 4	4	6
Passenger Heated Seat Back Element Ground		4
Passenger Heated Seat Cushion Element Control	B191A 39, 5	5	6
Passenger Heated Seat Cushion Element Ground		5
Ground		1
1. The driver and front passenger heated seats are inoperative. 2. The driver seat back heat function is inoperative 3. The driver seat cushion heat function is inoperative 4. Front passenger seat back heat function is inoperative 5. Front passenger seat cushion heat function is inoperative 6. Heated seat is always ON.

When a heated seat switch is pressed, a LIN bus serial data message is sent from the radio/HVAC controls to the HVAC control module. In turn the HVAC control module sends a low speed GMLAN serial data message to the body control module (BCM) indicating the heated seat command. The BCM serves as the heated seat system master to determine the requested operating mode. The BCM then sends a LIN bus serial data message to the seat heating control module indicating the heated seat command. The BCM also controls the seat temperature and mode indicators, via the serial data line, used to provide the operator with feedback as to the operating status of the system.

When the seat heating control module receives a heated seat command, it applies a high side drive pulse width modulated (PWM) signals driven at the required duty cycles to generate the appropriate effective voltage to the heating elements to attain the commanded seat temperature.

Schematic Reference

Heated/Cooled Seat Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Heated Seats Description and Operation

Electrical Information Reference

«Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON.
Verify the scan tool Body Control Module Driver Seat Heating Switch parameter changes between Inactive and Active when pressing the heated seat switch. If the parameter does not change Replace the A20 Radio/HVAC Controls. If the parameter changes
Verify the scan tool Body Control Module Passenger Seat Heating Switch parameter changes between Inactive and Active when pressing the heated seat switch. If the parameter does not change Replace the A20 Radio/HVAC Controls. If the parameter changes
Verify that both the driver and front passenger heated seats operate. If both the driver and front passenger heated seats are inoperative Refer to Circuit/System Testing - Both Heated Seats are Inoperative If just one of the heated seats is inoperative Refer to Circuit/System Testing - One Heated Seat Inoperative If both heated seats operate
All OK.

Both Heated Seats are Inoperative

Ignition OFF and all vehicle systems OFF, disconnect the X2 harness connector at the K29F Seat Heating Control Module - Front. It may take up to 2 min for all vehicle systems to power down.
Test for less than 10 ohms between the ground circuit terminal 7 and ground. If 10 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 10 ohms
Ignition ON.
Verify a test lamp illuminates between the B+ circuit terminals listed below and ground. Terminal 2 Terminal 3 If the test lamp does not illuminate and the circuit fuse is good Ignition OFF, remove the test lamp. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Ignition OFF, remove the test lamp. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K29F Seat Heating Control Module - Front. If the test lamp illuminates
Connect a 5 A fused jumper wire between each control circuit terminal listed below and B+, one at a time. Driver seat cushion terminal 4 Driver seat back terminal 8 Passenger seat cushion terminal 5 Passenger seat back terminal 6
Verify the fuse does not open between each test. If the fuse opens Repair the short to ground on the circuit. If the fuse does not open
Replace the K29F Seat Heating Control Module - Front.

One Heated Seat is Inoperative

Ignition OFF, disconnect the X2 harness connector at the K29F Seat Heating Control Module - Front, ignition ON.
Verify a test lamp illuminates between the B+ circuit terminal 2 and ground. If the test lamp does not illuminate and the circuit fuse is good Ignition OFF, remove the test lamp. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Ignition OFF, remove the test lamp. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K29F Seat Heating Control Module - Front. If the test lamp illuminates
Ignition OFF and all vehicle systems OFF, connect the X2 harness connector at the K29F Seat Heating Control Module - Front and disconnect the harness connector at the appropriate E14 Seat Heating Element. It may take up to 2 min for all vehicle systems to power down.
Test for less than 10 ohms between the ground circuit terminal B and ground. If 10 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 10 ohms
Connect a test lamp between the control circuit terminal A and ground, ignition ON.
Verify the test lamp turns ON and OFF when commanding the appropriate Driver or Passenger Seat Heating element ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, remove the test lamp, disconnect the X2 harness connector at the K29F Seat Heating Control Module - Front. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K29F Seat Heating Control Module - Front. If the test lamp is always ON Ignition OFF, remove the test lamp, disconnect the X2 harness connector at the K29F Seat Heating Control Module - Front, ignition ON. Test for less than 1 V between the control circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K29F Seat Heating Control Module - Front. If the test lamp turns ON and OFF
Test or replace the E14 Seat Heating Element.

Perform the Diagnostic Repair Verification after completing the repair.

«Driver or Passenger Seat Back Cushion Heater Replacement»(/cadillac/ats/i-2012-2014/remont/seats/#seat-heating-system-and-seat-cooling-system)
«Driver or Passenger Seat Cushion Heater Replacement»(/cadillac/ats/i-2012-2014/remont/seats/#seat-heating-system-and-seat-cooling-system)
«Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for K20 Radio/HVAC Controls and K29F Seat Heating Control Module - Front replacement, programming and setup

Scheme 82

Scheme 82: Front Seat Heater Control Module Replacement

Callout	Component Name
Preliminary Procedure Remove the front seat front extension cushion. Refer to Front Seat Front Extension Cushion Replacement
1	Front Seat Heater Control Module Fastener CAUTION: Refer to Fastener Caution .
2	Front Seat Heater Control Module Procedure Disconnect the electrical connector.

CAUTION
Refer to Fastener Caution .

Front Seat Heater Control Module Replacement

Scheme 83

Scheme 83: Driver or Passenger Seat Back Cushion Heater Replacement

Callout	Component Name
WARNING: Refer to SIR Warning . Preliminary Procedure Remove the driver or passenger seat. Refer to Driver or Passenger Seat Removal and Installation . Remove the driver or passenger seat back cushion cover and pad. Refer to Driver or Passenger Seat Back Cover and Pad Replacement (with AHE) , Driver or Passenger Seat Back Cover and Pad Replacement (without AHE) .
1	Driver or Passenger Seat Back Cushion Cover Procedure Separate the seat cushion from the seat cushion pad.
2	Driver or Passenger Seat Back Cushion Pad
3	Driver or Passenger Seat Back Cushion Heater Procedure Disconnect the electrical connector. Remove the heater element by peeling it off the seat back cushion pad. Apply service heater by removing the adhesive backing and attach to the gray strips of fabric inside the cushion trim. Align the notches in the fabric strips to those in the service heater. Place heater so that copper colored wires face the trim cover. If this is the second time for servicing, then remove the heater leaving the old adhesive strips intact on the seat cushion trim. The new seat heater adhesive strips will be placed over the old adhesive strips. Reassemble the trim to the cushion using hog ring tool.

WARNING
Refer to SIR Warning .

Driver or Passenger Seat Back Cushion Heater Replacement

Scheme 84

Scheme 84: Driver or Passenger Seat Cushion Heater Replacement

Callout	Component Name
WARNING: Refer to SIR Warning . WARNING: Replace the passenger presence system as a complete assembly to prevent possible injury to the occupant. All the components in the service kit are assembled and calibrated as a unit. Using only some of the components in the service kit will cause the passenger presence system to operate improperly. WARNING: To avoid personal injury, perform a preload test on the passenger presence system whenever you remove or replace the seat cushion trim. Failure to do so may cause the system to malfunction. Preliminary Procedure Disable the SIR system. Refer to. SIR Disabling and Enabling Remove the driver or passenger seat. Refer to. Driver or Passenger Seat Removal and Installation Remove the driver or passenger seat cushion pad. Refer to Driver or Passenger Seat Cushion Pad Replacement (with AHE) , Driver or Passenger Seat Cushion Pad Replacement (without AHE) .
1	Driver or Passenger Seat Cushion Cover
2	Driver or Passenger Seat Cushion Heater Procedure Disconnect the electrical connectors. The passenger presence system and heater element are both integral parts of the pad on the passenger seat cushion. Note the routing of the wiring harness and connector location for installation. Program the inflatable restraint passenger presence system after replacement. Refer to Control Module References

WARNING
Refer to SIR Warning .

WARNING
Replace the passenger presence system as a complete assembly to prevent possible injury to the occupant. All the components in the service kit are assembled and calibrated as a unit. Using only some of the components in the service kit will cause the passenger presence system to operate improperly.

WARNING
To avoid personal injury, perform a preload test on the passenger presence system whenever you remove or replace the seat cushion trim. Failure to do so may cause the system to malfunction.

Driver or Passenger Seat Cushion Heater Replacement

Heated Seat Components

The heated seat system consists of the following components

Radio/HVAC controls with heated seat switches
Body control module
Seat heating control module
Seat cushion heating element
Seat back heating element
Seat temperature control module

Note. The passenger seat block diagram is identical to the driver seat.

Scheme 85

Scheme 85: Heated Seat Block Diagram

Callout	Component Name
DA	Serial Data
HW	Hard-Wired
HW	Hard-Wired
HW	Hard-Wired
HW	Hard-Wired
A20	A20 Radio/HVAC Controls
K29	K29 Seat Heating Control Module
E14B	E14B Seat Heating Element - Driver Cushion
E14A	E14A Seat Heating Element - Driver Back
E14D	E14D Seat Heating Element - Passenger Cushion
E14C	E14C Seat Heating Element - Passenger Back

Heated Seat Switches

The driver and passenger heated seats switches are located in the radio/HVAC controls. The body control module (BCM) monitors each switch activation to determine which seat is activated and at what temperature level. With each press of the switch, the system will cycle through High, Medium, Low, and then back to Off again.

Heated Seat Operation

This heated seat system utilizes a self-regulating heating element system, which is different from the non-regulated heating element systems with seat temperature sensors previously used on GM vehicles. In the self-regulating type of system, temperature feedback to a control module is not required for temperature regulation. The heating element material itself regulates the surface temperature based on the effective voltage applied to the heating element.

Load Shed Management

The electrical power management function is designed to monitor the vehicle electrical load and determine when the battery is potentially in a high discharge condition. The heated seat system is one of the vehicle loads that is subject to reduction during a battery discharge condition. For more information on load management refer to Electrical Power Management Description and Operation .

Seat Heating System and Seat Cooling System Cadillac ATS I