GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1999 🢒 Catera 🢒 Body and Accessories 🢒 Lighting Systems 🢒 License and Tail Lamps Inoperative

Step

Action

Value(s)

Yes

No

DEFINITION: LH or RH rear license lamp or middle taillamp inoperative.

1

Did you perform the Exterior Lights Diagnostic System Check?

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Go to Step 2

Go to Exterior Lights System Check

2
  1. Turn the headlamp switch to the PARK position.
  2. Determine if the LH or RH rear license lamp or the middle taillamp is inoperative.

Is the middle taillamp inoperative?

--

Go to Step 3

Go to Step 8

3
  1. Disconnect the middle taillamp.
  2. Use the DMM in order to measure the voltage between terminal B of the middle taillamp connector and a known good ground.

Does the voltage measure near the specified value?

B+

Go to Step 5

Go to Step 4

4
  1. Locate an open or a high resistance in CKT RU12 and/or CKT RF1.
  2. Repair the open or the high resistance in CKT RU12 and/or CKT RF1.

Did you complete the repair?

--

Go to Step 19

--

5

Use the DMM in order to measure the resistance between terminal A of the middle taillamp connector and a known good ground.

Does the resistance measure less than the specified value?

5 ohms

Go to Step 7

Go to Step 6

6
  1. Locate an open or a high resistance in CKT F4 and/or CKT F48.
  2. Repair the open or the high resistance in CKT F4 and/or CKT F48.

Did you complete the repair?

--

Go to Step 19

--

7

Replace the middle taillamp. Refer to High Mount Stop Lamp Replacement in Lighting Systems.

Did you complete the repair?

--

Go to Step 19

--

8

Is the LH rear license lamp inoperative?

--

Go to Step 14

Go to Step 9

9
  1. Disconnect the RH rear license lamp connector.
  2. Use the DMM in order to measure the voltage between terminal C1 of the RH rear license connector and a known good ground.

Does the voltage measure near the specified value?

B+

Go to Step 11

Go to Step 10

10
  1. Locate an open or a high resistance in CKT RU3.
  2. Repair the open or the high resistance in CKT RU3.

Did you complete the repair?

--

Go to Step 19

--

11

Use the DMM in order to measure the resistance between terminal C2 of the RH rear license lamp connector and a known good ground.

Does the resistance measure less than the specified value?

5 ohms

Go to Step 13

Go to Step 12

12
  1. Locate an open or a high resistance in CKT F3.
  2. Repair the open or the high resistance in CKT F3.

Did you complete the repair?

--

Go to Step 19

--

13

Replace the RH rear license lamp. Refer to Rear License Lamp Replacement in Lighting Systems.

Did you complete the repair?

--

Go to Step 19

--

14
  1. Disconnect the LH rear license lamp connector.
  2. Use the DMM in order to measure the voltage between terminal C1 of the LH rear license lamp connector and a known good ground.

Does the voltage measure near the specified value?

B+

Go to Step 16

Go to Step 15

15
  1. Locate an open or a high resistance in CKT RU2.
  2. Repair the open or the high resistance in CKT RU2.

Did you complete the repair?

--

Go to Step 19

--

16

Use the DMM in order to measure the resistance between terminal C2 of the LH rear license lamp connector and a known good ground.

Does the resistance measure less than the specified value?

5 ohms

Go to Step 18

Go to Step 17

17
  1. Locate an open or a high resistance in CKT F2.
  2. Repair the open or the high resistance in CKT F2.

Did you complete the repair?

--

Go to Step 19

--

18

Replace the LH rear license lamp. Refer to Rear License Lamp Replacement in Lighting Systems.

Did you complete the repair?

--

Go to Step 19

--

19
  1. Connect all connectors and components that were disconnected.
  2. Verify that the LH and RH rear license lamps and the middle taillamp operate properly.

Do the LH and RH rear license lamps and the middle taillamp operate properly?

--

Go to Exterior Lights System Check

Go to Step 1