Grand Prix V6-191 3.1L VIN M SFI (1998)
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Testing For Short With Test Light Or DVM
WITH A SELF-POWERED TEST LIGHT OR OHMMETER.
1. Remove the blown fuse and disconnect the Battery and load.
2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side.
3. Connect the other lead to a known good ground.
4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the
self-powered test light or ohmmeter.
5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point.
FUSES POWERING SEVERAL LOADS
1. Find the schematic under Fuse Block Details, for the fuse that has blown.
2. Open the first connector or switch leading from the fuse to each load.
3. Replace the fuse.
^
If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described.
^
If fuse does not blow, refer to next step.
4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the
suspect circuit (disconnected) rather than at the fuse terminals.
Test Light/Digital Voltmeter
Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead,
touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being
tested.
A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much
voltage is present.
An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits
should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a
test light on circuits that contain solid state components, since damage to these components may result.
When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R)
connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact
surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting
Procedures/Checking Terminal Contacts
Connector Test Adapters
Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of
probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and
cause incorrect measurements.
Self-Powered Test Light
A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are
touched together, the bulb will go ON.