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

Step

Action

Value(s)

Yes

No

DEFINITION: LH or RH tail lamp is inoperative.

1

Did you perform the Exterior Lights Diagnostic System Check?

--

Go to Step 2

Go to Exterior Lights System Check

2
  1. Turn the headlamp switch to the PARK position.
  2. Determine which taillamp is inoperative.

Is the LH taillamp inoperative?

--

Go to Step 8

Go to Step 3

3
  1. Disconnect the RH taillamp.
  2. Use a DMM in order to measure the voltage between terminal C of the RH 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 RA4.
  2. Repair the open or the high resistance in CKT RA4.

Did you complete the repair?

--

Go to Step 13

--

5

Use the DMM in order to measure the resistance between terminal B of the RH 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 F25.
  2. Repair the open or the high resistance in CKT F25.

Did you complete the repair?

--

Go to Step 13

--

7

Replace the RH stop/taillamp lamp. Refer to Tail Lamp Bulb Replacement in Lighting Systems.

Did you complete the repair?

--

Go to Step 13

--

8
  1. Disconnect the LH taillamp.
  2. Use the DMM in order to measure the voltage between terminal B of the LH taillamp connector and a known good ground.

Does the voltage measure near the specified value?

B+

Go to Step 10

Go to Step 9

9
  1. Locate an open or a high resistance in CKT RF4.
  2. Repair the open or the high resistance in CKT RF4.

Did you complete the repair?

--

Go to Step 13

--

10

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

Does the resistance measure less than the specified value?

5 ohms

Go to Step 12

Go to Step 11

11
  1. Locate an open or a high resistance in CKT F125.
  2. Repair the open or the high resistance in CKT F125.

Did you complete the repair?

--

Go to Step 13

--

12

Replace the LH stop/taillamp. Refer to Tail Lamp Bulb Replacement Lighting Systems.

Did you complete the repair?

--

Go to Step 13

--

13
  1. Connect all of the connectors and components that were previously disconnected.
  2. Verify that the LH and RH taillamps turn on.

Do the LH and RH taillamps turn on?

--

Go to Exterior Lights System Check

Go to Step 1