Checking the Horn

Fault symptom
The horn sounds continuously.

Diagnostic procedure
1 Connect the Intelligent Saab Tester (ISAT): Select the "ACTIVATE" menu and then "HORN ON/OFF". Activate the horn with "ON". It should now sound.
2 If it does not, select the ISAT menu "OBTAIN READOUTS" (leaving the "activate" function "ON") and then select "HORN RELAY". Read the display.
Horn activated-> "ACTIVE"
3 If point 2 is OK, connect the BOB and check the voltage across pin 24 of the control module and a good grounding point.
The voltage should be about 12 V.
If the voltage is OK, proceed to point 5,
4 If the voltage is not OK, check the wiring for shorting to ground by measuring the resistance across:
- pin 1 of the 33-pin connector (blue) below the left-hand A-pillar and the horn's red lead.
- the horn's yellow lead and pin 24 of the control module connector.
The resistance should be < 1 ohm.
If the resistance is OK, the horn is at fault. Install a new horn.
5 Check the grounding by measuring the resistance across pin 22 of the control module and a good grounding point.
The resistance should be < 1 ohm.
If the resistance is not OK, check the wiring for a short circuit.