Horn System Diagnostic Tests; Horn System Circuit Test - Case IH AFX8010 Repair Manual

HORN SYSTEM DIAGNOSTIC TESTS

NOTE: The batteries must be fully charged and all connections clean and tight. Use a multimeter (DVOM) for
these tests.
DO NOT use a self-powered test light for any of these tests. Use of a self-powered test light can cause
damage to components in this system.
Before performing any of the electrical tests, be sure all operating controls are in neutral or park lock
position. This will eliminate accidental movement of the machine or start-up of power driven equipment.
Test Point
1 Close Horn Switch located
in the Road Light Switch.
Check for 12 volts at horn
connector X172 (pin 1).
2 Close Horn Switch located
in the Road Light Switch.
Check for 12 volts at Road
Light Switch connector
X256 (pin 9).
3 Check for 12 volts at Road
Light Switch connector
X256 (pin 8).
4 Check for 12 volts at Fuse
F51.
5 Check resistance of circuit
631 (BK) between horn
connector X172 (pin 2) and
ground.
BODY AND STRUCTURE - USER PLATFORM
CAUTION
WARNING

HORN SYSTEM CIRCUIT TEST

Good Reading
12 volts
If good reading, go to test
point 5.
12 volts
If good reading, repair
open in circuit 193 (WH).
Check in-line connector
X004 (pin 18) for
connection.
12 volts
If good reading, replace
Road Light Switch.
12 volts
If good reading, repair
open in circuit 214 (RD).
Less than 1 ohm
If good reading, horn power
and ground circuits okay. If
horn does not work,
replace horn.
E.34 / 32
Possible Cause of Bad Reading
Open in B+ circuit 193 (WH) between
Road Light Switch connector X256 (pin
9) and Horn connector X172 (pin 1).
Go to next test point.
Horn Switch.
Go to next test point.
Open B+ circuit 214 (RD) between Road
Light Switch connector X256 (pin 8) and
Fuse F51.
Go to next test point.
Blown Fuse F51.
Open in B+ circuit. See Power
Distribution for testing.
Open circuit 631 (BK) between horn and
ground.