HHR L4-2.2L (2007)
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Checking Aftermarket Accessories
CHECKING AFTERMARKET ACCESSORIES
Do not connect aftermarket accessories into the following circuits:
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CAUTION: Refer to SIR Caution.
SIR circuits, all such circuits are indicated on circuit diagrams with the SIR symbol.
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NOTE: Refer to OBD II Symbol Description Notice.
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:
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Power feeds connected to points other than the battery
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Antenna location
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Transceiver wiring located too close to vehicle electronic modules or wiring
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Poor shielding or poor connectors on antenna feed line
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Check for recent service bulletins detailing installation guidelines for aftermarket accessories.
Circuit Protection - Circuit Breakers
CIRCUIT PROTECTION - CIRCUIT BREAKERS
A circuit breaker is a protective device that is designed to open the circuit when a current load is in excess of the rated breaker capacity. If there is a short
or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. Two types of circuit
breakers are used.
CIRCUIT BREAKER
This type opens when excessive current passes through it for a period of time. It closes again after a few seconds, and if the cause of the high current is
still present, it will open again. The circuit breaker will continue to cycle open and closed until the condition causing the high current is removed.
POSITIVE TEMPERATURE COEFFICIENT (PTC) CIRCUIT BREAKER
This type greatly increases its resistance when excessive current passes through it. The excessive current heats the PTC device, as the device heats its
resistance increases. Eventually the resistance gets so high that the circuit is effectively open. Unlike the ordinary circuit breaker the PTC unit will not
reset until the circuit is opened, by removing the voltage from its terminals. Once the voltage is removed the circuit breaker will re-close within a
second or 2.
Circuit Protection - Fuses
CIRCUIT PROTECTION - FUSES