Bravada 2WD L6-4.2L VIN S (2002)
Accessory Delay Module: Diagnostic Aids
Basic Knowledge Required
Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained. You should understand the basic theory of
electricity and know the meaning of voltage (volts), current (amps) and resistance (ohms). You should be able to read and understand a diagnostic aid as
well as understand what happens in a circuit with an open or a shorted wire.
Checking Aftermarket Accessories
Do not connect aftermarket accessories into the following circuits:
CAUTION: Refer to SIR Handling Caution in Service Precautions.
^
SIR circuits, all such circuits are indicated on circuit diagrams with the SIR symbol.
NOTE: Refer to OBD II Symbol Description Notice in Service Precautions.
^
OBD II circuits, all such circuits are indicated on circuit diagrams with the OBD II symbol.
Always check for aftermarket accessories (non-OEM) as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the
system to verify that these add-on accessories are not the cause of the problems.
Possible causes of vehicle problems related to aftermarket accessories include:
^
Power feeds connected to points other than the battery
^
Antenna location
^
Transceiver wiring located too close to vehicle electronic modules or wiring
^
Poor shielding or poor connectors on antenna feed line
^
Check for recent service bulletins detailing installation guidelines for aftermarket accessories.
Inducing Intermittent Fault Conditions
In order to duplicate the customer's concern, it may be necessary to manipulate the wiring harness if the malfunction appears to be vibration related.
Manipulation of a circuit can consist of a wide variety of actions, including:
^
Wiggling the harness
^
Disconnecting a connector and reconnecting
^
Stressing the mechanical connection of a connector
^
Pulling on the harness or wire in order to identify a separation/break inside the insulation
^
Relocating a harness or wires
All these actions should be performed with some goal in mind. For instance, with a scan tool connected, wiggling the wires may uncover a faulty input to
the control module. The snapshot option would be appropriate here. Refer to Scan Tool Snapshot Procedure. You may need to load the vehicle in order
to duplicate the concern. See: General Electrical Diagnostic Procedures/Circuit Testing/Scan Tool Snapshot Procedure
This may require the use of weights, floorjacks, jackstands, frame machines, etc. In these oases you are attempting to duplicate the concern by
manipulating the suspension or frame. This method is useful in finding harnesses that are too short and their connectors pull apart enough to cause a poor
connection. A DMM set to Peak Min/Max mode and connected to the suspect circuit while testing can yield desirable results. Refer to Testing for
Electrical Intermittents. See: Diagrams/Diagnostic Aids
Certainly, using the senses of sight, smell, and hearing while manipulating the circuit can provide good results as well.
There may be instances where circuit manipulation alone will not meet the required criteria for the fault condition to appear. In such cases it may be
necessary to expose the suspect circuit to other conditions while manipulating the harness. Such conditions would include high moisture conditions,
along with exceptionally high or low temperatures. The following discusses how to expose the circuit to these kinds of conditions.
Salt Water Spray
Some compounds possess the ability to conduct electricity when dissolved in water such as ordinary salt. By mixing table salt with water in sufficient
quantities, you can enhance the conductive properties of water so that any circuit which may be sensitive to moisture will more readily fail when
liberally sprayed with this mixture.
Mixing 0.35L (12 oz) of water with approximately 1 tablespoon of salt will yield a salt solution of 5 percent. Fill a normal spray bottle with this
mixture. This mixture is sufficient to enhance the water's own conductivity. This may cause the circuit to fail more easily when sprayed. Once the
mixture is completed, spray the suspect area liberally with the solution. Then, while monitoring either a scan tool or DMM, manipulate the harness as
discussed previously.
High Temperature Conditions
TOOLS REQUIRED
