Preliminary Electrical Checks
all these paragraphs very carefully! The picture below represents
a common area of truck electrical problems. The starter picture
is concerned with the heavy cables which connect the battery to
the starter and also connect the battery to all other electrical
circuits on the truck.
In this picture, those cables are sheathed in the light grey cable
guards. All truck electrical supply current passes through these
heavy cables, and a loose or oxidized connection can cause very
unusual electrical problems throughout the truck.
You may have noticed some nasty looking goop on these connectors
on the new trucks. This is an attempt to prevent oxidation by
sealing out harmful moisture and salt spray. While driving on
winter roads, the salt spray under your hood creates a very hostile
environment for your electrical cables and connectors.
you are experiencing weird electrical problems or engine power
loss on E-engines (E-engines is trucker slang for electronic or
computer controlled diesel engines), you had better check these
cables for tightness! The loose or oxidized connection forms a
high resistance, and the E-engine
computer starts doing strange things because of this high resistance.
In fact, it has been suggested that more than 90% of todays E-engine
problems are due to high resistance problems with the computer
power source or the engine sensors.
Before working on any of these cables, disconnect the battery
ground cable (the black one) from the batteries. Failure to disconnect
the batteries before tightening these connectors, could result
in personal burns, eye injury, damaged parts, and damaged tools.
If you don't know how to disconnect the batteries, refer the job
to a professional. Try to rotate the cables around the lug, using
a non-metallic object for leverage. If you can move the connector
(cable flexing does not count), it needs tightening. Sometimes,
oxidation of the connection will cause problems, even when the
connection is physically tight. This is especially true of battery
post connections. The fix for invisible oxidation problems, is
to first slightly loosen the connection, then rotate the connection,
feeling the physical friction of movement. This will rub off any
oxidation, and form new non-oxidized electrical surfaces. This
method may work for battery posts, but the recommended procedure
for battery connectors is to completely remove the connector and
clean the battery post and the inside of the connector. Now, retighten
the connector and then reconnect the batteries.
or oxidized battery cable connections normally cause start up
problems, but it never hurts to check these connections as part
of your preliminary checks.
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