GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Theft Deterrent System Schematics

Connector End View Reference: Component Connector End Views

DEFINITION: The turn signal lamps do not flash (left and or right side) when content theft deterrent (CTD) is armed or disarmed and do not flash when alarm is tripped.

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Do the hazard lamps operate from the switch?

Go to Step 3

Go to Symptoms - Lighting Systems

3

  1. Open the driver and passenger windows.
  2. Remove the keys from the ignition.
  3. Close all the doors, rear compartment and the hood.
  4. Lock the doors with the transmitter.
  5. Note the status of the left and right turn signal lamps.

Did either the left or the right signal lamp flash?

Go to Step 4

Go to Step 5

4

  1. Disconnect the intelligent switching unit (ISU).
  2. Test the inoperative turn signal lamp control circuit for an open. Refer to Testing for Continuity and Wiring Repairs .

Did you find and correct the condition?

Go to Step 7

Go to Step 5

5

Test for a poor connection at the ISU. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 7

Go to Step 6

6

Important:  Perform the program procedure for the ISU.

Replace the ISU.

Did you complete the replacement?

Go to Step 7

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7

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2