General Information

Suitable instruments for diagnosing faults in the car's electrical system are an Intelligent Saab Tester (ISAT) Scan Tool, a voltmeter and an ohmmeter.
^ Use an ISAT Scan Tool or voltmeter for measuring the voltage in a circuit.

^ If the voltmeter is of analogue type, it should have an internal resistance of at least 20 Megohm/V.

^ Use an ISAT Scan Tool or ohmmeter for measuring the resistance of a circuit.

^ The ohmmeter must NOT be used for taking readings on components containing semiconductors, such as control modules and time-delay relays, etc.

^ When measuring resistance, the voltage supply to the system being tested must be disconnected as the test instrument feeds a small current into the circuit being tested.

This will ensure that no current is already flowing through the circuit and that a correct reading will be obtained.