Jumper Lead Feature; Checking For Bad Ground Contacts; Following And Locating Short Circuits - Forch 5439 172 Manual Del Usuario

Jumper lead feature

The Testing Device Switch's negative battery hook-up lead and auxiliary lead are connected directly through the Testing Device
Switch. By leaving the positive hook-up disconnected from the vehicle's battery, the Testing Device Switch can be used as a
long jumper lead.
Be careful to avoid short circuits and overloading when using this jumper function. The leads, in this configuration,
are NOT protected by the Testing Device's circuit breaker.
Positive hook-up
clips hangs loose
Positive current is
now flowing directly
through this lead and
is activating the relay

Checking for bad ground contacts

Probe the suspected ground wire or contact with the probe tip.
Observe the green LED indicator.
Depress the power switch forward then release.
If the LED indicator changed from GREEN to RED, this is not a true ground.
If the circuit breaker tripped, this circuit is more than likely a direct ground. Keep in mind that high current components such as
starter motors will also trip the circuit breaker.

Following and locating short circuits

In most cases a short circuit will appear by a fuse or a fusible link blowing or a protection device tripping (i.e., a circuit breaker).
This is the most convenient place to begin the search. Remove the shorted out fuse from the fuse box.
Use the Testing Device's tip to energize each of both contacts in the fuse box. The side which trips the Testing Device's circuit
breaker is the shorted circuit. Take note of this wire's identification code or color. Follow the wire as far as you can along the
wiring harness, for instance if you are following a short in the brake light circuit you may know that the wire must pass through the
wiring harness at the door sill. Locate the colour-coded wire in the harness and expose it. Probe through the insulation of the
wire with the Testing Device's tip and depress the power switch forward to energize the wire. If theTesting Device's circuit
breaker tripped you have verified the shorted wire. Cut the wire and energize each end with the Testing Device's tip. The wire
which trips the Testing Device's ciruit breaker again will lead you to the shorted area.
Follow the wire in the shorted direction and repeat this process until the short is located.