
Switches & Relays
Switches are used in electrical circuits to control the passage of current. The most
common use is to open and close circuits between the battery and the various electric
devices in the system. Switches are rated according to the amount of amperage they can
handle. If sufficient amperage rated switch is not used in a circuit, the switch could
overload and cause damage.
Underhood fuse and relay panel
Some electrical components which require a large amount of current to operate use a
special switch called a relay. Since these circuits carry a large amount of current, the
thickness of the wire in the circuit is also greater. If this large wire were connected from the
load to the control switch, the switch would have to carry the high amperage load and the
fairing or dash would be twice as large to accommodate the increased size of the wiring
harness. To prevent these problems, a relay is used.
Relays are composed of a coil and a set of contacts. When the coil has a current passed
though it, a magnetic field is formed and this field causes the contacts to move together,
completing the circuit. Most relays are normally open, preventing current from passing
through the circuit, but they can take any electrical form depending on the job they are
intended to do. Relays can be considered "remote control switches." They allow a smaller
current to operate devices that require higher amperages. When a small current operates
the coil, a larger current is allowed to pass by the contacts. Some common circuits which
Содержание TrailBlazer
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Страница 26: ...Fig 3 Typical body and undervehicle maintenance locations Refer to chart for descriptions ...
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Страница 59: ...Cylinder head bolt removal and installation 32 Remove and discard the bolts from the cylinder head ...
Страница 175: ...Spring free length check Valve spring squareness check ...
Страница 192: ...Front of piston mark ...
Страница 361: ...5 3L Engine Except Saab Underhood Fuse Block 2003 2005 Early Production ...
Страница 469: ...Removing the outer band from the CV boot Removing the inner band from the CV boot ...
Страница 470: ...Removing the CV boot from the joint housing Clean the CV joint housing prior to removing boot ...
Страница 471: ...Removing the CV joint housing assembly Removing the CV joint ...
Страница 472: ...Inspecting the CV joint housing Removing the CV joint outer snap ring ...
Страница 473: ...Checking the CV joint snap ring for wear CV joint snap ring typical ...
Страница 474: ...Removing the CV joint assembly Removing the CV joint inner snap ring ...
Страница 475: ...Installing the CV joint assembly typical ...
Страница 506: ...Tie Rod End Removal Installation Inner Tie Rod End To Remove Inner tie rod assembly Magnasteer ...
Страница 553: ...9 Torque the lug nuts to specification 10 Lower the vehicle ...
Страница 556: ...Toe in Frame Misalignment Frame misalignment ...
Страница 588: ...Bleeding caliper ...
Страница 596: ...Inboard brake pad removal and installation 10 Remove the inboard brake pad from the brake caliper ...
Страница 624: ...Manifold gauge set components Refrigerant recovery recycling station ...
Страница 662: ...Lower instrument panel retaining volts 25 Remove the lower retaining bolts from the instrument panel I P ...
Страница 676: ...A C Specifications ...
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