Where is the horn relay? - 2003 Ford Expedition

Do you have an air bag light lit on the instrument cluster ? Do you have C.C. button's on the steering wheel , do they work ? If the alarm fob (as u call it ) Can make the horns sound , the relay is sending B+ voltage to the horns Don't know how your testing.
System Description
The horn system consists of the following components:
• Horn fuse
• Horn relay
• Horn switch
• Horn(s)
• Body Control Module (BCM)
System Operation
The vehicle horns are activated under the following conditions:
• The horn switch is depressed.
• The body control module (BCM) commands the horns on. The BCM commands the horns on under either of the following conditions:
- When the content theft deterrent system detects a vehicle intrusion. For further information, refer to Content Theft Deterrent (CTD) Description and Operation in Theft Deterrent.
- When the panic button is depressed on the remote control door lock transmitter. For further information, refer to Keyless Entry System Description and Operation in Keyless Entry.
- When the OnStar® system is used to sound the horns, if equipped. For further information, refer to OnStar Description and Operation in Cellular Communications.
- When the keyless entry system is used to lock the vehicle, a horn chirp may sound to notify the driver that the vehicle has been locked. The notification feature may be enabled or disabled through personalization. For further information, refer to Keyless Entry System Description and Operation in Keyless Entry.

Circuit Operation
Battery positive voltage is applied at all times to the horn relay coil and the horn relay switch. Pressing the horn switch applies ground to the horn relay control circuit. The body control module BCM may also apply ground to the horn relay control circuit as described above. When the horn relay control circuit is grounded, the horn relay is energized and battery positive voltage is applied to the horn(s) through the horn control circuit. The horn(s) sound as long as ground is applied to the horn relay control circuit.

The horn system consists of a single horn, a horn relay located in the underhood fuse block, and driver controlled horn switch in the steering wheel. The horn system is designed to provide the driver with an audible warning to signal pedestrians, other drivers, etc.
Operation
Voltage is supplied to the horn relay coil and contacts at all times through a 10 amp HORN fuse, located in the underhood fuse block. When the driver pushes the horn pad, driver air bag module, the circuit completes and energizes the horn relay coil. This causes the horn relay contact to close. When the contact closes, current travels to the horn and the horn emits an audible warning.

System Description
The horn PCB relay is non replaceable ,soldered to the underhood fuse / relay box. . You would have to take the box a part to get at it . Is the air bag light lit on the instrument cluster ? Could have an open wire in the Clock spring , do you know what a clock spring is ? It is inside the upper part of the steering column , It allows the steering wheel to be turned full right to full left keeping the horn an all the buttons an air bag connected electrically. When the horn button is pressed, ground is applied through the horn switch contacts and the horn relay control circuit to the coil side of the relay. The horn relay coil is then energized, causing the relay switch contacts to close applying voltage through the horn control circuit to the horns. For theft deterrent functions, the body control module (BCM) also controls the horn relay by applying ground to the relay control circuit to the relay.
Circuit/System Testing
With a test lamp connected to ground, probe each of the test points on the HORN fuse while activating the horns. The test lamp should illuminate at one or both of the fuse test points.
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If the test lamp does not illuminate at either test point, refer to the Horn Switch Test.

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If the test lamp illuminates, refer to the Horn Test.

Ignition OFF, disconnect the inline harness connector C275. Ignition ON, test for B+ between the horn relay control circuit terminal B and ground.
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If less than B+, test the control circuit for an open/high resistance. If the circuit tests normal, replace the underhood fuse block.

Momentarily connect a 3-A fused jumper wire between the control circuit terminal B and ground. The horns should work.
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If the horns do not work, replace the underhood fuse block.

If all circuits test normal, test or replace the horn switch

The PCB relay horn system consists of the following components:
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Horn switch

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Horn PCB relay

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Horn assembly

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Body control module (BCM)

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HORN fuse 15 A

How cars clock spring works

Check your wiring diagram and check for power coming out of the horn relay. Suspect a bad relay.

The horn relay primary receives + full time and is actuated by receiving ground (-) from the horn button. Check ground continuity at the horn button (at the steering wheel) to make sure it is working first (most likely culprit). If the horn button is working, check to see if the horn relay is working (second most likely culprit). To test the horn relay, provide chassis or battery ground to the (-) primary terminal of the horn relay and see if the horn honks. If it does, that will tell you that the problem is in the wiring between the steering wheel and the relay, most likely a disconnected wire at the steering column.
The only other components in the system are the fuse for the horn circuit (if you have 12v at the horn relay, that is fine), and the horn itself. My bet is on the horn button pad itself.

If you know the fuse and relay have power, you should be able to jumper the relay and make the horn blow. The horn pad on the steering wheel usually grounds the relay. If you can jumper the relay and make the horn blow, the problem may be the horn pad or the clockspring in the steering column.

The problem is one of three possibles:

1. The horn switch (button) on the steering wheel.
2. The horn relay.
3. The wiring associated with the two items above.

If you press the horn button and know where the horn relay is, you can listen for it to activate. If it does, then either the relay's output contacts are bad or the wiring between the relay and horn is faulty. If the relay doesn't activate, test for voltage at the relay coil with an multimeter in the relay socket. If there is voltage there when the horn button is pressed, then the relay is bad. If there is no voltage there, the the horn button or associated wiring is faulty.

No the Chevy Malibu is not made by Kia!
I think you mean horn relay
I would try a new relay it is possible that the relay is defective and that's why it was removed
here is how the horn circuit works
The body control module (BCM) controls the horn relay by grounding the control circuit of the horn relay coil. When the horn relay coil is grounded, the horn relay contacts close, applying voltage to the horn via the horn supply voltage circuit.
if the horn relay does not fix your concern you may need to take it to a shop and check for any BCM fault codes
and you are correct having no horn is a SAFETY ISSUE
that car should have NEVER PASSED A SAFETY WITHOUT A HORN
hope this helps good luck and I hope the relay fixs it because a BCM is costly

The horn relay is faulty or the horn is dead.Try tapping on the horn while someone is holding in the horn button,if that make the horn work the it's the horn,if not,change the relay.

one relay is going to work both horns if there are two horns.
horns are different than relays.
all horns are ran from one relay.
the horns are only different in sounds.
if one horn is not working and the other is its the horn itself.
disconnect the horn itself and listen for the relay clicking .