Check Security Horn

CHECKING STEPS REFERENCE

Step	Check	Yes	No
1 CHECK SECURITY HORN RELAY. Remove and check the security horn relay. < Ref. to SECURITY HORN RELAY . >	Is the security horn relay OK?	Go to step 2.	Replace the security horn relay.
2 CHECK POWER SUPPLY FOR SECURITY HORN RELAY. Measure the voltage between the security horn relay harness connector terminal and chassis ground. Connector & terminal Without OnStar models (B243) No. 1 (+) - Chassis ground (-): With OnStar models (B243) No. 3 (+) - Chassis ground (-):	Is the measured value more than 10 V?	Go to step 3.	Check the harness for open circuits and shorts between the security horn relay and horn relay.
3 CHECK POWER SUPPLY FOR SECURITY HORN RELAY. Measure the voltage between the security horn relay harness connector terminal and chassis ground. Connector & terminal Without OnStar models (B243) No. 2 (+) - Chassis ground (-): With OnStar models (B243) No. 1 (+) - Chassis ground (-):	Is the measured value more than 10 V?	Go to step 4.	Check the harness for open circuits and shorts between the security horn relay and the fuse.
4 CHECK HARNESS BETWEEN SECURITY HORN RELAY AND SECURITY CONTROL MODULE. Disconnect the security control module harness connector. Measure the resistance between the security horn relay harness connector terminal and security control module harness connector terminal. Connector & terminal Without OnStar models (B243) No. 3 - (B93) No. 18: With OnStar models (B243) No. 4 - (B93) No. 18:	Is the measured value less than 10 Ω?	Go to step 5.	Check the harness for open circuits and shorts between the security horn relay and security control module.
5 CHECK HARNESS BETWEEN SECURITY HORN RELAY AND SECURITY CONTROL MODULE. Measure the resistance between the security horn relay harness connector terminal and security control module harness connector terminal. Connector & terminal Without OnStar models (B243) No. 4 - (B93) No. 16: With OnStar models (B243) No. 2 - (B93) No. 16:	1 Is the measured value less than 10 Ω?	Go to step 6.	Check the harness for open circuits and shorts between the security horn relay and security control module.
6 CHECK HARNESS BETWEEN SECURITY CONTROL MODULE AND SECURITY HORN. Disconnect the security horn harness connector. Measure the resistance between the security control module harness connector terminal and security horn harness connector terminal. Connector & terminal (B93) No. 17 - (B204) No. 1:	Is the measured value less than 10Ω?	Go to step 7.	Check the harness for open circuits and shorts between the security control module and security horn.
7 CHECK SECURITY HORN. Remove and check the security horn. < Ref. to SECURITY HORN . >	Is the security horn OK?	Replace the security control module.	Replace the security horn.