LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Subaru >> 2004 >> Forester XT, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 176 (Security And Locks) >> Security System >> Inspection >> Check Security Horn
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Check Security Horn

WARNING: This page is about a different car, the 2005 Subaru Forester. However, it is still accessible from the selected car via links, so may be relevant.
CHECKING SECURITY HORN

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 
(B243) No. 1 (+) - chassis ground (-): 		 Is the voltage 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 
(B243) No. 2 (+) - chassis ground (-): 		 Is the voltage 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 UNIT. 
  1. Disconnect the security control unit harness connector.
  2. Measure the resistance between the security horn relay harness connector terminal and security control unit harness connector terminal.

Connector & terminal 
(B243) No. 3 - (B93) No. 18: 		 Is the resistance less than 10 ohm? Go to step 5.  Check the harness for open circuits and shorts between the security horn relay and security control unit.
5 : CHECK HARNESS BETWEEN SECURITY HORN RELAY AND SECURITY CONTROL UNIT. 
Measure the resistance between the security horn relay harness connector terminal and security control unit harness connector terminal.
Connector & terminal 
(B243) No. 4 - (B93) No. 16: 		 Is the resistance less than 10 ohm? Go to step 6.  Check the harness for open circuits and shorts between the security horn relay and security control unit.
6 : CHECK HARNESS BETWEEN SECURITY CONTROL UNIT AND SECURITY HORN. 
  1. Disconnect the security horn harness connector.
  2. Measure the resistance between the security control unit harness connector terminal and security horn harness connector terminal.

Connector & terminal 
(B93) No. 17-(B204) No. 1: 		 Is the resistance less than 10 ohm? Go to step 7.  Check the harness for open circuits and shorts between the security control unit 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 unit. Replace the security horn.
scientia non olet · About LEMON Manuals