Using the DC Volts Scale
If measuring less than 10V DC, use the 10V
Use the DC volts scale to measure all voltages; the AC
jack. If measuring less than 2.5V DC, use the
volts scale is never used on these semitrailers.
Setting up the Meter. Before reading the meter, set
(c) To measure 12V DC, plug the red lead
it up using the procedure below that matches the
into the 50V jack on the left side of the meter.
If you are not sure of the voltage you will be
measuring, ALWAYS select the 50V range
(100V range on the AN/URM-105).
(1) AN/URM-105. Set the meter switch to the
DC volts range set forth in the testing paragraph for the
component or circuit you are testing. (For most circuits on
the semitrailer, the right range is the one marked 100 DC
If measuring less than 10V DC, set switch to
the V/DC 10 position. If measuring less than
2.5V DC, set switch to the V/DC 2.5 position.
(a) Set the polarity reversing switch to the
+ DC position.
(a) Set the FUNCTION switch to DIRECT.
(b) Put the black lead in the DC+/-AC/