
Jumper wires are simple, yet extremely valuable, pieces of test equipment. They are
basically test wires which are used to bypass sections of a circuit. Although jumper wires
can be purchased, they are usually fabricated from lengths of standard automotive wire
and whatever type of connector (alligator clip, spade connector or pin connector) that is
required for the particular application being tested. In cramped, hard-to-reach areas, it is
advisable to have insulated boots over the jumper wire terminals in order to prevent
accidental grounding. It is also advisable to include a standard automotive fuse in any
jumper wire. This is commonly referred to as a "fused jumper". By inserting an in-line fuse
holder between a set of test leads, a fused jumper wire can be used for bypassing open
circuits. Use a 5 amp fuse to provide protection against voltage spikes.
Jumper wires are used primarily to locate open electrical circuits, on either the ground (
–)
side of the circuit or on the power (+) side. If an electrical component fails to operate,
connect the jumper wire between the component and a good ground. If the component
operates only with the jumper installed, the ground circuit is open. If the ground circuit is
good, but the component does not operate, the circuit between the power feed and
component may be open. By moving the jumper wire successively back from the
component toward the power source, you can isolate the area of the circuit where the
open is located. When the component stops functioning, or the power is cut off, the open is
in the segment of wire between the jumper and the point previously tested.
You can sometimes connect the jumper wire directly from the battery to the "hot" terminal
of the component, but first make sure the component uses 12 volts in operation. Some
electrical components, such as fuel injectors or sensors, are designed to operate on about
4 to 5 volts, and running 12 volts directly to these components will cause damage.
Test Lights
12 volt test light
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 ...
Страница 677: ......