GM Service Manual Online
For 1990-2009 cars only

All Stoplamps are Inoperative (Export)

Step

Action

Value(s)

Yes

No

1

Were you sent here from the Exterior Lights Diagnostic System Check?

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Go to Step 2

Go to Exterior Lights Diagnostic System Check

2

Check the 20 amp STP/HAZ MiniFuse® #8 for an open circuit.

Is the fuse open?

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Go to Step 6

Go to Step 3

3

  1. Disconnect the stoplamp switch connector C2.
  2. Connect a DMM between the stoplamp switch connector C2 terminal A and ground.
  3. Measure the voltage at the stoplamp switch connector.

Is the voltage within the specified values?

10.0-14.0V

Go to Step 5

Go to Step 4

4

Repair an open in CKT 140 between the instrument panel electrical center connector C1 terminal B2 and the stoplamp switch connector C2 terminal A.

Is the repair complete?

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Go to Exterior Lights Diagnostic System Check

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5

  1. Reconnect the stoplamp switch connector C2.
  2. Connect the DMM at the stoplamp switch connector C2 terminal B.
  3. Depress the brake pedal.
  4. Measure the available voltage at the stoplamp switch connector C2 terminal B.

Is the voltage within the specified values?

10.0-14.0V

Go to Step 13

Go to Step 18

6

Replace the 20 amp STP/HAZ MiniFuse® #8.

Does the fuse short open when replace?

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Go to Step 7

Go to Step 8

7

Repair a short to ground in CKT 140 between the instrument panel electrical center connector C1 terminal B2 and the stoplamp switch connector C2 terminal A.

Is the repair complete?

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Go to Exterior Lights Diagnostic System Check

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8

  1. Disconnect the underhood electrical center connector C2.
  2. Connect a DMM between the stoplamp switch connector C2 terminal B and ground.
  3. Check for continuity to ground at the stoplamp switch connector terminal B.

Is continuity to ground present?

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Go to Step 9

Go to Step 10

9

Repair a short to ground in CKT 20 between the stoplamp switch connector C2 terminal A and the underhood electrical center connector C2 terminal F1.

Is the repair complete?

--

Go to Exterior Lights Diagnostic System Check

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10

  1. Disconnect the underhood electrical center connector C1.
  2. Disconnect the connector C140.
  3. Connect a DMM between the underhood electrical center connector C3 terminal A1 and ground.
  4. Check for continuity to ground at the underhood electrical center connector C3 terminal A1.

Is continuity to ground present?

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Go to Step 11

Go to Step 12

11

Repair a short to ground in CKT 20 between connector C140 terminal F and the underhood electrical center connector C3 terminal A1.

Is the repair complete?

--

Go to Exterior Lights Diagnostic System Check

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12

Repair a short to ground in CKT 820 between the connector C140 terminal F and the electronic brake traction control module or the stoplamp (LH, RH, CHMSL) light bulbs.

Is the repair complete?

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Go to Exterior Lights Diagnostic System Check

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13

  1. Disconnect the connector C140.
  2. Connect a DMM between the connector C140 terminal F (leading towards the stoplamp switch) and ground.
  3. Depress the brake pedal.
  4. Measure the available voltage at the connector C140 terminal F.

Is the voltage within the specified values?

10.0-14.0V

Go to Step 15

Go to Step 14

14

Repair an open in CKT 20 between the stoplamp switch connector C2 terminal B and connector C140 terminal F.

Is the repair complete?

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Go to Exterior Lights Diagnostic System Check

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15

  1. Reconnect the connector C140.
  2. Remove the LR tail/stop lamp bulb from its socket.
  3. Connect a DMM between the LR stop lamp positive terminal and ground.
  4. Depress the brake pedal.
  5. Measure the available voltage at the LR stop lamp positive terminal within the lamp socket.

Is the voltage within the specified values?

10.0-14.0V

Go to Step 16

Go to Step 17

16

Repair an open in CKT 150 between the splice pack 400 and the G401.

Is the repair complete?

--

Go to Exterior Lights Diagnostic System Check

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17

Repair an open in CKT 820 between the connector C140 terminal F and the stoplamp (LH, RH, CHMSL) light bulbs.

Is the repair complete?

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Go to Exterior Lights Diagnostic System Check

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18

  1. Check for a poor connection or a misalignment of the stoplamp switch.
  2. If OK, replace the stoplamp switch.

Is the repair complete?

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Go to Exterior Lights Diagnostic System Check

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