Hudson 1955 Rambler, Technical & Service Manual

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E L E C T R I C A L
43
licensemounting bracket.
Bulb #T-63 (Trade Number) 3 cp 6-8 volts
HORNS AND RELAYS
The horn circuit includes a matched pair of
horns, the horn relay, the battery, the horn
button, and the car frame. With the relay in
the circuit, the button is required to carry
only the relay control current. Therefore,
the spark formed when the button contacts
open is much less than it would be if all
current flowed through the button.
The "Hornet" and "Wasp" Series horns are
mounted on the right and left wheelhouse
panel extensions behind the radiator grille.
The "Rambler" Series straight twin horns
and relay assembly are mounted on the right
front wheelhouse panel underneath the hood.
The horn button contact plates are actuated
by the horn ring or button contained in the
steering wheel. The horn button wire has a
bayonet connection at the lower end of the
steering post under the hood.
Each horn consists of a diaphragm vibrated
rapidly by an electromagnet. When the
electromagnet is energized, it pulls on an
armature attached to the diaphragm. The
slight movement of the armature flexes the
diaphragm and also opens a set of contacts.
With the contacts open, the electromagnet is
no longer energized and the diaphragm
returns to its original shape. This closes
the contacts and the cycle is repeated.
The constant flexing and straightening of
the diaphragm produces vibration and sound.
A resistance unit is connected across the
contact points to reduce arcing and prolong
contact life.
The horn relay consists of an electromag-
net and a set of contacts arranged so that
when the magnet is energized an armature is
attracted and the contacts close. A spring
keeps the contacts open when the unit is at
rest.
Horn Wiring
Inspect the wiring between the horn, button,
relay, and battery for loose connections,
chafed insulation, corroded terminals, and
for partial breaks—especially where the
leads enter a conduit or are clamped by a
terminal. This inspection should include the
battery ground strap and the grounding of the
horn through its mounting bracket.
If the horns do not operate when the horn
ring is depressed, check for breaks in the
horn button circuit by grounding the relay
"S" terminal. If the horns operate, the horns
and relay are not defective. Then the horn
button and lead should be thoroughly in-
spected.
The usual cause of continuous operation
of the horns is a ground in the horn button
wiring. To check, disconnect the horn button
lead from the relay "S" termimal. If this
stops the horn operation, inspect the button
lead for grounds especially where it enters
the steering column. If the horns do not stop
when the "S" terminal lead is removed,
disconnect the other leads from the relay and
inspect the relay.
Horn Maintenance
The horns should be cleaned and inspected
periodically. If horns are rusted or corroded,
they should be removed for overhaul or
replacement. If the horn mounting is cracked
or loose, repairs should be made.
To test whether the horns are inoperative,
connect a jumper lead from the battery to the
horn terminal. The horns should operate with
this lead in place. If they do not, ground the
horn frame to the chassis to check the horn
ground connection. If the horns now operate,
the ground connection is at fault and the horn
should be removed and the mounting surfaces
cleaned.
Hornet" and "Wasp" Series
If the horns are inoperative, or do not have
a steady clear tone, they should be removed,
cleaned, and disassembled. To remove the horn
dome, place a screw driver between the dome
head and the projection and loosen.
Inspect the diaphragm for cracks and
distortion and inspect the windings and
connections for breaks, faulty insulation,
and grounds.
Horn Relay Maintenance
To check the relay operation, ground the relay
horn button terminal. If the relay does not
close with the terminal grounded, check the
wiring and horns as described previously and
remove the relay for a complete test.
"Hornet" and "Wasp" Series
The relay coil resistance is 4.5 ohms taken
through the coil from the "S" and "B" termi-
nals.
The normal amperage draw for the low pitch
horn is 13-17 amperes @ 5-7 volts. The normal
amperage draw for the high pitch horn is 12-16
amperes @ 5-7 volts.
"Rambler" Series
Clean relay points with contact file. Bend
brass strip on top of armature to readjust
points to .03125" plus or minus .010".
SPEEDOMETERS
King-Seeley type speedometers are used. They
are the magnetic type.
For servicing of the speedometer head
within warranty, it is recommended that the
head be replaced with a unit from stock. For
maintenance service after the warranty peri-
od, the speedometer head should be