Chery A1 2009 Service Manual page 18

Sensors & Relays
• Gently apply a slight vibration to sensors and relays in the system you are inspecting. This test may indicate a
loose or poorly mounted sensor or relay.
Engine Compartment
• There are several reasons a vehicle or engine vibration could cause an electrical complaint. Some of the things
to check for are:
− Connectors not fully seated.
− Wiring harness not long enough and is being stressed due to engine vibrations or rocking.
− Wires laying across brackets or moving components.
− Loose, dirty or corroded ground wires.
− Wires routed too close to hot components.
• To inspect components under the hood, start by verifying the integrity of the ground connections (See Ground
Inspection described later). First, verify that the system is properly grounded. Then check for any loose connec-
tions by gently shaking the wiring or components as previously explained. Using the electrical schematics,
inspect the wiring for continuity.
Behind The Instrument Panel
• An improperly routed or improperly clamped harness can become pinched during accessory installation. Vehicle
vibration can aggravate a harness which is routed along a bracket or near a mounting screw.
• An unclamped or loose harness can cause wiring to be pinched by seat components (such as slide guides)
during vehicle vibration. If the wiring runs under seating areas, inspect wire routing for possible damage or
pinching.
Heat Sensitivity Test
The customer's concern may occur during hot weather or after the vehicle has sat for a short time. In such cases you
will want to check for a heat sensitive condition.
To determine if an electrical component is heat sensitive, heat the component with a heat gun or equivalent.
CAUTION:
Do not heat components above 60°C (140°F).
If the incident occurs while heat testing the component, replace or properly insulate the component as needed.
Freezing Test
The customer may indicate the incident goes away after the vehicle warms up (winter time). The cause could be
related to water freezing somewhere in the wiring/electrical system. There are two methods to check for this:
• The first method is to arrange for the owner to leave the vehicle overnight. Make sure it will get cold enough to
duplicate the complaint. Leave the vehicle parked outside overnight. In the morning, do a quick and thorough
diagnosis of those electrical components which could be affected.
• The second method is to put the suspect component into a freezer long enough for any water to freeze. Rein-
stall the part on the vehicle and check for a reoccurrence of the incident. If it occurs, repair or replace the
component as needed.
Water Intrusion Test
The incident may occur only during high humidity or in rainy/snowy weather. In such cases the incident could be
caused by water intrusion on an electrical part. This can be simulated by soaking the car or running it through a car
wash.
Electrical Load Test
The incident may be electrical load sensitive. Perform diagnosis with all accessories (including A/C, rear window
defogger, radio, fog lamps) turned on.
Cold or Hot Starting Test
On some occasions an electrical incident may occur only when the vehicle is started cold, or it may occur when the
vehicle is restarted hot shortly after being turned off. In these cases you may have to keep the vehicle overnight to
make a proper diagnosis.
Chery Automobile Co., Ltd.
DIAGNOSING ELECTRICAL FAILURES
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