1. Disconnect the negative battery cable..
2. Remove the following parts:
a. Trunk end trim.
b. Rear scuff plate (RH).
c. Trunk side trim (RH).
d. Theft-deterrent horn.
3. Apply battery positive voltage to horn terminal A, and connect the horn retaining bolt to ground as shown in the figure, and then verify that the horn sounds.

If the horn does not sound, replace the horn.
Remote Transmitter Battery Voltage Inspection
Theft Deterrent Horn Removal/InstallationAutomatic Transaxle Removal/Installation [Fw6 A EL]
CAUTION:
Performing the following procedures without first removing the front ABS
wheel-speed sensor may possibly cause an open circuit in the harness if it is
pulled by mistake. Before performing the following procedures, disconnect the
front ABS wheel-speed sensor (axle side) and ...
Oil Pressure Switch [Fw6 A EL, Fw6 Ax EL]
Purpose/Function
The oil pressure switch detects the engagement pressures of the low clutch,
2-6 brake, R-3-5 brake, and the high clutch.
The oil pressure switch signal is used for automatic shift control, manual
shift control, TCC control, line pressure control, direct electric ...
Lights On Reminder Warning Alarm
Purpose
The lights-on reminder warning alarm notifies the driver that the TNS and
headlights are not turned off.
Function
The instrument cluster receives the following vehicle condition signals via
the CAN signal from the start stop unit and rear body control module (RBCM). ...