Dodge RAM TRUCK 1500 1995 Service Manual page 451

8G - 2 HORNS B R
(d) The coil battery terminal (86) is connected to
the electromagnet in the relay, and battery voltage
should be present at all times. If battery voltage is
not present at relay cavity 86, check circuit to fuse
B. Repair as required.
(e) The coil ground terminal (85) is connected to
the electromagnet in the relay. It is grounded when
the horn switch is depressed. Check for continuity
to ground at relay cavity 85 with the horn switch
depressed. If no continuity is found with hom
switch depressed, or if continuity is found with
horn switch released, repair horn switch or wiring
as required. See Horn Switch Remove/Install in
this group for service procedures.
If all relay connections are OK, go to next step.
RELAY TERMINALS RELAY CAVITIES
87A
J958A-2
TERMINAL LEGEND
NUMBER IDENTIFICATION
30 COMMON FEED
85 COIL GROUND
86 COIL BATTERY
87 NORMALLY OPEN
87A NORMALLY CLOSED
Fig. 1 Horn Relay Connections
(3) With the horn relay still removed, check the
horn relay by performing the following tests:
(a) A relay in the de-energized position should
have continuity between terminal 87A and termi­
nal 30, and no continuity between terminal 87 and
terminal 30.
(b) Resistance value between terminals 85 and
86 (electromagnet) is 75±5 ohms.
(c) Connect a battery to terminals 85 and 86.
There should now be continuity between terminal
87 and terminal 30.
If relay fails any of the above tests, replace faulty
relay. If relay checks OK, reinstall and go to next
step.
(4) Disconnect wiring at horn terminal. Depress
horn switch. There should be battery voltage at the
dark green/red wire of the horn wiring connector. If
OK, go to next step. If not OK, repair circuit to relay
as required.
(5) Measure the resistance between the black wire
of the horn wiring connector and a good chassis
ground. The meter should read zero ohms. If OK, re­
place faulty horn(s). If not OK, repair circuit to
ground as required.
HORN SWITCH
WARNING: B E F O R E BEGINNING ANY A I R B A G S Y S ­
TEM COMPONENT REMOVAL OR INSTALLATION,
R E M O V E AND ISOLATE THE NEGATIVE (-) C A B L E
FROM THE BATTERY. THIS IS THE ONLY S U R E
WAY TO D I S A B L E THE A I R B A G S Y S T E M . FAILURE
TO DO THIS COULD R E S U L T IN ACCIDENTAL AIR-
B A G DEPLOYMENT AND P O S S I B L E INJURY. WAIT 2
MINUTES FOR THE A I R B A G S Y S T E M CAPACITOR
TO DISCHARGE B E F O R E REMOVING OR WORKING
ON ANY A I R B A G S Y S T E M COMPONENTS.
(1) Disconnect battery negative cable. Remove
knee blocker. Check for continuity between metal
steering column jacket and a good ground. There
should be continuity. If OK, go to next step. If not
OK, refer to Group 19 - Steering and check for proper
installation of steering column ground clip.
(2) Remove horn relay from fuseblock module. Ac­
cess horn switch wire connector as described in Horn
Switch Remove/Install. Unplug horn wire connector.
Check for continuity between steering column half of
horn switch wire connector and a good ground. There
should be no continuity. If OK, go to next step. If not
OK, repair short circuit as required.
(3) Check for continuity between steering column
half of horn switch wire connector and horn relay
cavity 1. There should be continuity. If OK, go to
next step. If not OK, repair open circuit as required.
(4) Check for continuity between horn switch half
of horn switch wire connector and a good ground.
There should be no continuity. If OK, go to next step.
If not OK, replace faulty horn switches.
(5) Depress one horn switch and check for continu­
ity between horn switch half of horn switch wire con­
nector and a good ground. There should be
continuity. Repeat test for other horn switch. If either
switch is not OK, replace faulty horn switches.