Troubleshooting Equipment
VOLTMETER AND TEST LAMPUse a test lamp or a voltmeter on circuits without solid- state units and use a test lamp to check for voltage. A test lamp 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.
CAUTION: A number of circuits include solid-state modules, such as the Engine Control Module (ECM), used with computer command control Injection. Voltage in these circuits should be tested only with a 10-mega Ohm or higher impedance digital voltmeter. Never use a test lamp on circuits that contain solid-state modules. Damage to the modules may result.
A voltmeter can be used in place of a test lamp. While a test lamp shows whether the voltage is present or not, a voltmeter indicates how much voltage is present.
SELF-POWERED TEST LAMP AND OHMMETER
Use a self-powered test lamp or an ohmmeter to check for continuity. The ohmmeter shows how much resistance there is between two points along a circuit. Low resistance means good continuity.
CAUTION: Never use a self-powered test lamp on circuits that contain solid state modules. Damage to these modules may result
An ohmmeter can be used in place of a self-powered test lamp. The ohmmeter shows how much resistance there is between two points along a circuit. Low resistance means good continuity.
Circuits which include any solid-state devices should be tested only with a 10-mega Ohm or higher impedance digital multimeter. When measuring resistance with a digital multimeter, the battery negative terminal should be disconnected. Otherwise, there may incorrect readings. Diodes and solid-state devices in a be circuit can make an ohmmeter give a false reading. To find out if a component is affecting a measurement, take one reading, reverse the leads and take a second reading. If different the solid-state device is affecting the measurement.
JUMPER WIRE WITH FUSE
Use a jumper wire with a fuse to by-pass an open circuit.
A jumper wire is made up of an in-line fuse holder connected to a set of test leads. This tool is available with small clamp connectors providing adaption to most connectors without damage.
CAUTION: Do not use a fuse with a higher rating than the specified fuse that protects the circuit being tested. Do not use this tool in any situation to substitute an input or output at the solid-state control module, such as ECM, TCM, etc.
SHORT FINDER
A short finder is available to locate a short to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal.