5 XF 95 series Fault finding DIAGNOSTICS 3. FAULT FINDING The following test equipment and tools can be used to trace faults. 1. The best instrument for this is a digital multimeter. This instrument can be used to measure voltages, currents and resistances avoiding reading errors, and it can be used to trace virtually any faults. 2. Many, but not all, faults are easily traced by means of warning lamps. Failures caused by poor earthing cannot normally be detected by a warning lamp or buzzer. 1 The most frequently occurring faults are: a. short circuit b. open circuits c. earthing problems (poor earthing due to corrosion). 200303 3-1