Troubleshooting Tests

Fig.6 Electrostatic Discharge Symbol:

STANDARD PROCEDURE - ELECTROSTATIC DISCHARGE (ESD) SENSITIVE DEVICES
All ESD sensitive components are solid state and a symbol (Fig. 6) is used to indicate this. When handling any component with this symbol, comply with the following procedures to reduce the possibility of electrostatic charge build up on the body and inadvertent discharge into the component. If it is not known whether the part is ESD sensitive, assume that it is.

1. Always touch a known good ground before handling the part. This should be repeated while handling the part and more frequently after sliding across a seat, sitting down from a standing position, or walking a distance.
2. Avoid touching electrical terminals of the part, unless instructed to do so by a written procedure.
3. When using a voltmeter, be sure to connect the ground lead first.
4. Do not remove the part form it's protective packing until it is time to install the part.
5. Before removing the part from it's package, ground the package to a known good ground on the vehicle.

Fig.7 Testing For Voltage Potential:

STANDARD PROCEDURE - TESTING FOR VOLTAGE POTENTIAL
1. Connect the ground lead of a voltmeter to a known good ground (Fig. 7).
2. Connect the other lead of the voltmeter to the selected test point. The vehicle ignition may need to be turned ON to check voltage. Refer to the appropriate test procedure.

STANDARD PROCEDURE - TESTING FOR CONTINUITY
1. Remove the fuse for the circuit being checked or, disconnect the battery.

Fig.8 Testing For Continuity:

2. Connect one lead of the ohmmeter to one side of the circuit being tested (Fig. 8).
3. Connect the other lead to the other end of the circuit being tested. Low or no resistance means good continuity.

STANDARD PROCEDURE - TESTING FOR A SHORT TO GROUND
1. Remove the fuse and disconnect all items involved with the fuse.
2. Connect a test light or a voltmeter across the terminals of the fuse.
3. Starting at the fuse block, wiggle the wiring harness about 6 - 8 inches apart and watch the voltmeter/test lamp.
4. If the voltmeter registers voltage or the test lamp glows, there is a short to ground in that general area of the wiring harness.

STANDARD PROCEDURE - TESTING FOR A SHORT TO GROUND ON FUSES POWERING SEVERAL LOADS
1. Refer to the wiring diagrams and disconnect or isolate all items on the suspected fused circuits.
2. Replace the blown fuse.
3. Supply power to the fuse by turning ON the ignition switch or re-connecting the battery.
4. Start connecting or energizing the items in the fuse circuit one at a time. When the fuse blows the circuit with the short to ground has been isolated.

Fig.9 Testing For Voltage Drop:

STANDARD PROCEDURE - TESTING FOR A VOLTAGE DROP
1. Connect the positive lead of the voltmeter to the side of the circuit closest to the battery (Fig. 9).
2. Connect the other lead of the voltmeter to the other side of the switch, component or circuit.
3. Operate the item.
4. The voltmeter will show the difference in voltage between the two points.