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Digital Multimeters

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When diagnosing electrical problems on automobiles and trucks, it is important to use a quality digital multimeter.  Most vehicle manufacturers recommended a particular digital multimeter to use when diagnosing electrical problems on their vehicles.  Fluke meters seem to be the favorite among vehicle manufacturers; visit www.fluke.com for more information on each meter. 

The following list shows the recommended digital multimeter for each vehicle manufacturer:

  • DaimlerChrysler - Fluke 73-III, Fluke 77-III, Fluke 78-A, or Fluke 88.

 

  • Ford - Fluke 77-III

  • General Motors - Fluke 87-III (2004 - The Fluke 87-III has been replaced by the Fluke 87-V meter shown below right).

  

  • Honda - Fluke 88

  • Toyota - Fluke 87-III or Fluke 1520 (2004 - The Fluke 87-III has been replaced by the Fluke 87-V meter shown below left).

   

The Fluke 87-III and 87-V multimeters are the only True RMS meters shown above.  This is only important if the vehicle manufacturer, like General Motors and Toyota, recommend this feature.  If a voltage measurement specification is given in true RMS, but it is measured with a non-true RMS meter, it may not measure the same voltage.

Any meter you decide to purchase should also have an internal impedance of at least 10MΩ (10 Million Ohms).  See the documentation of your meter to see what its impedance is.  Think of the internal impedance of a meter as indicating the resistance that the meter offers a circuit it is measuring.  Without this high internal resistance, the meter would affect the current and voltage of the circuit you are measuring causing inaccurate readings and possible circuit damage.

The Fluke 87 multimeter is the most widely used multimeter in the automotive industry.  General Motors and Toyota both recommend the use of this meter.  Because of the wide-spread use of this meter it will be used for all examples in this course.  Although there are other meters shown above and many others not shown, they all have similar functions, screen symbols, buttons, and measurement procedures. 

Copyright 2008, by the Contributing Authors. Cite/attribute Resource. jfrank. (2008, February 12). Digital Multimeters. Retrieved November 22, 2009, from WSU Web site: http://ocw.weber.edu/automotive-technology/ausv-1320-automotive-electronics/5-understanding-a-dmm/digital-multimeters. This work is licensed under a Creative Commons License. Creative Commons License