6-76-7TX / TXH / TXB 180S - 400L (Rev. 4/23/07)TX / TXH / TXB 180S - 400L (Rev. 4/23/07)
is released, the is released, the circuit will open. circuit will open. This switch This switch isis
checked like an On-Off switch with the exceptionchecked like an On-Off switch with the exception
that the switch must be held closed to completethat the switch must be held closed to complete
resistance checks.resistance checks.
Solenoids.Solenoids. A solenoid is A solenoid is an electrical compo-an electrical compo-
nent. nent. When electricity When electricity is applied to is applied to the coil, tthe coil, thehe
solenoid will solenoid will form an form an electromagnet. electromagnet. The magnet-The magnet-
ic field will pull or push an armature into the coilic field will pull or push an armature into the coil
(based on application). (based on application). The armature The armature can be ccan be con-on-
nected to a switch in electrical circuits to turn thenected to a switch in electrical circuits to turn the
switch on or ofswitch on or off. f. An armature can also An armature can also be used tobe used to
open or close valves.open or close valves.
Solenoids employed as electrical switches can beSolenoids employed as electrical switches can be
troubleshot with an ohmmtroubleshot with an ohmmeter. eter. Remove the Remove the twotwo
wires from the two larger posts of the solenoid.wires from the two larger posts of the solenoid.
Energize the solenoid. Energize the solenoid. With an ohmWith an ohmmetermeter, check, check
the resistance the resistance between the between the two larger two larger posts. posts. TheThe
ohmmeter should indicate between 0 - 40 ohmsohmmeter should indicate between 0 - 40 ohms
nominally.nominally.
Solenoids employed as hydraulic switches areSolenoids employed as hydraulic switches are
used to used to open and close open and close spools of spools of valves. valves. TheThe
gg
readings should indicate a higher ohm resistancereadings should indicate a higher ohm resistance
in one direction opposed to the other directionin one direction opposed to the other direction
because the current generated by the ohmmeterbecause the current generated by the ohmmeter
is sufficient enough to forward-bias the diode.is sufficient enough to forward-bias the diode.
CCaatthhooddee AAnnooddee
Current FlowCurrent Flow
Illustration Illustration 6-5. 6-5. DiodeDiode
Refer to Illustrations 6-6 and 1-6 for component referenceRefer to Illustrations 6-6 and 1-6 for component reference
CCoommppoonneenntt PPrroobblleemm CCoorrrreeccttiioonn
11.. BBaatttteerryy
11. L. Loow w vvoollttaaggee.. 11..
a. a. Low electrolyLow electrolyte level. te level. CheckCheck
electrolyte level in battery, fillelectrolyte level in battery, fill
with distilled water as required,with distilled water as required,
and recharge battery.and recharge battery.
b. b. Alternator output Alternator output is bad. is bad. ReferRefer
to the Alternator troubleshoot-to the Alternator troubleshoot-
ing section below.ing section below.
c. Loose, broken, or corrodedc. Loose, broken, or corroded
wires. wires. Repair or Repair or replace wreplace wires.ires.
d. Ensure that low voltage condi-d. Ensure that low voltage condi-
tion has not been caused bytion has not been caused by
accessories having been leftaccessories having been left
on for extended periods ofon for extended periods of
time.time.
22.. AAlltteerrnnatatoorr
1.1. Low Low outoutput put volvoltagtage (ve (voltoltage age isis
below 12 VDC).below 12 VDC).
1.1.
a. Ensure drive belts are tight.a. Ensure drive belts are tight.
b. Inspect the wiring for defects.b. Inspect the wiring for defects.
Check all connections for tight-Check all connections for tight-
ness and cleanliness, includ-ness and cleanliness, includ-
ing the slip connectors at theing the slip connectors at the
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