Airstream INTERNATIONAL TRAILER Owner's Manual page 94

AIRSTREAM INTERNATIONAL TRAILER OWNERS MANUAL
TROUBLE SHOOTING
The most common failure in the exterior electrical system is an open circuit. An open circuit is an
interruption in the current flow, which may be in either the wire to the component or in the ground return.
Check the following areas for open circuits:
1. Light bulb (filament open.)
2. Loose or corroded connections at lighting device.
3. Loose or corroded connections at 7 way connectors
4. Improper grounding at the lighting device,
A continuity light or an ohmmeter will help you isolate the point of the "open" on the circuit. Another cause
of failure is a short circuit usually resulting in a blown fuse or cycling circuit breaker at the power source.
The wire coming in contact with a sharp edge usually causes a short. The sharp edge wears the wire's
insulation away until the "hot" wire short to ground.
Locating Shorts and Opens
The key in locating shorts and opens is isolation. The first step is to isolate the circuit with the short or open
and then isolate the section of the circuit with the fault. Once the section is identified, the specific problem
can be located. The cause may be a loose or corroded connection, cut wire, worn insulation, defective
component, etc. The following paragraphs describe methods of isolating shorts and opens. There are
several other approaches that may be used; however, these may be used as a guide.
Shorts
1. Locate circuit that has short by noting fuse blown or cycling breaker.
2. Remove fuses or wire from breaker, and open all switches. Check for continuity between (+) 12-volt
wire or shorted circuit and ground. (If it cannot be determined if the switch is in the open position, remove
the lead from the switch.) Continuity to ground indicates there is a short.
3. Remove leads of shorted circuits from converter and components one at a time. After disconnecting each
component, check continuity of the (+) 12-volt wire to ground. If there is no continuity the short is in the
component removed. If continuity still exists, continue with the following steps.
4. Inspect leads carefully where they pass through the skin or near sharp edges.
5. Note objects attached to skin after manufacturing. The mounting screws or rivets may be causing the
short.
6. Remove multi-dome to expose main body of harness. Inspect harness for cause of short, such as rivets or
screws in harness or evidence of drilling.
7. If short cannot be found, cut circuit into sections, checking each section for continuity. Shorts can be
isolated by this method.
8. Examples of shorts are:


The (+) 12-volt wire contacting (-) negative wire or grounded surface.
Internal short in a 12-volt component or appliance.
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