GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2005 🢒 DeVille 🢒 Accessories 🢒 Navigation Systems 🢒 DTC B3642

Circuit Description

The seat cool temperature switch is normally open. When the switch is pressed, it momentarily sends a 12-volt signal through the cool temperature switch signal circuit to the door control module. The door module then sends the cooled seat request to the heated/cooled seat module (CCSM). In response to this signal, the heated/cooled seat module activates the cooled seat mode.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B3642 Seat Cooler Switch Circuit

Conditions for Running the DTC

The door module must be powered and cannot have B1327 - Battery Voltage Low or B1328 - Battery Voltage High set as an active DTC for this DTC to set.

Conditions for Setting the DTC

If the door module detects that the seat cool temperature switch input circuit is active for 30 continuous seconds, the switch will be considered shorted and the DTC will set.

Action Taken When the DTC Sets

No other heated/cooled seat switch activations shall be recognized as a result of this switch circuit being active.

Conditions for Clearing the DTC

The DTC automatically clears when the switch circuit setting the DTC is no longer active.

Test Description

The number below refers to the step number on the diagnostic table.

  1. This step checks the existing state of the seat cool temperature switch by using the current state of the input parameter.

Step

Action

Yes

No

Schematic Reference: Driver Seat Schematics or Passenger Seat Schematics

Connector End View Reference: Power Seat Connector End Views or Power Door Systems Connector End Views in Doors

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Seat Cool Mode Switch parameter in the appropriate Door Module Input data list.

Does the Seat Cool Mode Switch parameter display OFF?

Go to Step 3

Go to Step 4

3
  1. Activate the seat cool temperature switch.
  2. With a scan tool, observe the Seat Cool Mode Switch parameter.

Does the Seat Cool Mode Switch parameter change state?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 4

4
  1. Turn OFF the ignition.
  2. Disconnect the heated/cooled seat switch connector.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the Seat Cool Mode Switch parameter.

Does the Seat Cool Mode Switch parameter display OFF?

Go to Step 7

Go to Step 5

5

Test the seat cool temperature switch signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 6

6

Inspect for poor connections at the harness connector of the door control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 8

7

Inspect for poor connections at the harness connector of the heated/cooled seat switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 9

8

Replace the door control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 10

--

9

Replace the heated/cooled seat switch. Refer to Heated and Cooled Seat Switch Replacement .

Did you complete the replacement?

Go to Step 10

--

10
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC, as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK