GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1999 🢒 Eldorado 🢒 Body and Accessories 🢒 Horns 🢒 Horns Inoperative

Step

Action

Value(s)

Yes

No

1

Was the Horn System Check performed?

--

Go to Step 2

Go to Horns System Check

2

Use a scan tool in order to command the horns ON then OFF.

Did the horns sound?

--

Go to Step 4

Go to Step 3

3
  1. Disconnect the horn relay.
  2. Connect a test lamp between the horn relay connector terminal A6 and ground.

Is the test lamp on?

--

Go to Step 6

Go to Step 5

4
  1. Disconnect C202.
  2. Connect a test lamp between C202 terminal A12 (body harness half) and ground.

Is the test lamp on?

--

Go to Step 8

Go to Step 7

5

Repair the open or short to ground in CKT 742 (RED).

Is the repair complete?

--

Go to Horns System Check

--

6

Connect a test lamp between the horn relay connector terminal A4 and ground.

Is the test lamp on?

--

Go to Step 10

Go to Step 9

7

Repair the open in CKT 28 (BLK).

Is the circuit repair complete?

--

Go to Horns System Check

--

8
  1. Inspect CKT 28 (BLK) for an open.
  2. Inspect for proper contact at C202 terminal A12.
  3. Inspect for proper contact at the horn brush ring.
  4. Inspect for proper contact of ground at the horn switch.
  5. If OK, replace the horn switch.

Is the repair complete?

--

Go to Horns System Check

--

9

Repair the open or short to ground in CKT 742 (RED).

Is the repair complete?

--

Go to Horns System Check

--

10
  1. Connect a test lamp between the horn relay connector terminal A6 and terminal B4.
  2. Press the horn switch.

Is the test lamp on?

--

Go to Step 12

Go to Step 7

11
  1. Disconnect the left and right horns.
  2. Connect a fused jumper between the relay terminal A6 and terminal B6.
  3. Connect a test lamp between the horn connector terminal B and ground.
  4. Repeat the procedure for each horn.

Did the test lamp light?

--

Go to Step 15

Go to Step 13

12

Connect a fused jumper between the horn relay terminal A4 and terminal B6.

Did the horns sound?

--

Go to Step 14

Go to Step 11

13

Repair the open in CKT 29 (DK GRN).

Is the repair complete?

--

Go to Horns System Check

--

14
  1. Inspect the horn relay connector for clean and tight connections.
  2. If OK, replace the horn relay.

Is the repair complete?

--

Go to Horns System Check

--

15

Repair the open in CKT 650 (BLK).

Is the repair complete?

--

Go to Horns System Check

--