Product Manual

7.3 FAULT INDICATION

OPEN CIRCUIT

The MUTT® senses no load which is often the symptom of a disconnected wire, cut

wire, poor pin connection or bad return ground. The MUTT® can detect open circuits

in two ways.

1. During Ground Integrity Test: An individual circuit will blink and no audible alerts

will be present.

2. During circuit selection: The selected circuit’s LED will blink, while simultaneously the

Open Circuit Indicator will ash. The MUTT® will also provide an audible alert (beep).

Example: The MUTT® detects an open circuit in the Clearance Light Circuit. The

Clearance LED will blink, the Open Circuit Indicator will ash and the MUTT® will

beep.

NOTE: Open Circuit Indicator will only illuminate during circuit selection.

CROSSED CIRCUITS

The MUTT® indicates that two or more circuits are back feeding or crossed. This

can be a symptom of two wires in the same harness wearing through their insulated

coating and connecting.

1. When a crossed circuit is identied, the selected circuit LED will illuminate steadily and

the circuit it is crossed with will ash. The MUTT® will also provide an audible alert beep).

Example: The MUTT® detects that the Clearance and Tail/Tag are crossed while the

Clearance Circuit is selected. The Clearance LED will illuminate, the Tail/Tag LED will

ash and the MUTT® will beep.

NOTE: In some cases, a crossed circuit may be a normal function of advanced

diagnostic testing, such as with certain ABS systems.

Example: Open Circuit in Clearance Light

Example: Crossed Circuit in Clearance and Tail/Tag Lights