Finding A Short Circuit - Toyota Automobile Electrical Repair And Modification

INTRODUCTION–HOW TO PERFORM FOR SYSTEM INSPECTION
To Ignition SW
IG Terminal
Test Bulb
Disconnect
Light
SW2
4.
Fuse Case
Short [A]
SW1
Short [B]
Disconnect
Relay
Short [C]
Disconnect
Solenoid
Wire Harness Repair Manual (RM1022E)

Finding a Short Circuit

(a) Remove the blown fuse and eliminate all loads from
the fuse.
(b) Connect a test bulb in place of the fuse.
(c) Establish conditions in which the test bulb comes on.
Example:
[A] – Ignition SW on
[B] – Ignition SW and SW 1 on
[C] – Ignition SW, SW 1 and Relay on (Connect the Relay)
and SW 2 off (or disconnect SW 2)
(d) Disconnect and reconnect the connectors while
watching the test bulb. The short lies between the
connector where the test bulb stays lit and the
connector where the bulb goes out.
(e) Find the exact location of the short by lightly shaking
the problem wire along the body.
CAUTION:
(a) Do not open the cover or the case of the ECU
unless absolutely necessary. (If the IC terminals
are touched, the IC may be destroyed by static
electricity.)
(b) When replacing the internal mechanism (ECU
part) of the digital meter, be careful that no part of
your body or clothing comes in contact with the
terminals of leads from the IC, etc. of the
replacement part (spare part).
A–7
A
11