Troubleshooting; Voltage Check; Continuity And Resistance Check - Toyota Tundra 2003 Electrical Wiring Diagram

C TROUBLESHOOTING
To Ignition SW
IG Terminal
Fuse
SW 1
Relay
Solenoid
SW 2
Ohmmeter
SW
Ohmmeter
Diode
Digital Type
12
[A]
Voltmeter
[B]
[C]
Analog Type
2003 TOYOTA TUNDRA (EWD491U)

VOLTAGE CHECK

(a) Establish conditions in which voltage is present at the check
point.
Example:
[A] – Ignition SW on
[B] – Ignition SW and SW 1 on
[C] – Ignition SW, SW 1 and Relay on (SW 2 off)
(b) Using a voltmeter, connect the negative lead to a good ground
point or negative battery terminal, and the positive lead to the
connector or component terminal.
This check can be done with a test light instead of a voltmeter.

CONTINUITY AND RESISTANCE CHECK

(a) Disconnect the battery terminal or wire so there is no voltage
between the check points.
(b) Contact the two leads of an ohmmeter to each of the check
points.
If the circuit has diodes, reverse the two leads and check
again.
When contacting the negative lead to the diode positive side
and the positive lead to the negative side, there should be
continuity.
When contacting the two leads in reverse, there should be no
continuity.
(c) Use a volt/ohmmeter with high impedance (10 kΩ/V
minimum) for troubleshooting of the electrical circuit.