Ford 2003 Mustang Workshop Manual page 3313

Are the resistances correct?
A4 CHECK WIRE BETWEEN HORN RELAY AND HORN
Key in OFF position.
Disconnect: Horn C1262.
Disconnect: Horn C1261.
Measure the resistance between the horn relay connector Pin 3,
Circuit 1 (DB), harness side and horn C1261 or horn C1256
harness side; and between the horn relay connector Pin 3, Circuit
1 (DB), harness side and ground.
Is the resistance less than 5 ohms between the horn relay and
the horns, and greater than 10,000 ohms between the horn
relay and ground?
A5 CHECK WIRE BETWEEN HORN RELAY AND AIR BAG SLIDING
CONTACT
Key in OFF position.
Deactivate the air bag system; refer to
Disconnect: Air Bag Sliding Contact C218a.
Measure the resistance between air bag sliding contact C218a Pin
2, Circuit 6 (YE/LG), harness side and horn relay connector Pin 1,
Circuit 6 (YE/LG) harness side.
Is the resistance less than 5 ohms?
A6 CHECK AIR BAG SLIDING CONTACT
Disconnect the steering wheel switch harness from the air bag
sliding contact.
Measure the resistance between upper air bag sliding contact
Section 501-20B .
Yes
INSTALL new horns.
TEST the system for
normal operation.
No
REPAIR the circuit.
TEST the system for
normal operation.
Yes
GO to A6 .
No
REPAIR the circuit.
TEST the system for
normal operation.
Yes
GO to A7 .