Envoy 2WD V6-4.3L VIN W (1998)
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 two.
Fuses
The fuse is the most common method of an automotive wiring circuit protection. Whenever there is an excessive amount of current flowing through a
circuit the fusible element will melt and create an open or incomplete circuit. Fuses are an one time protection device and must be replaced each time the
circuit is overloaded. To determine if a fuse is open, remove the suspected fuse and examine the element in the fuse for an open (break). If not broken,
also check for continuity using a J 39200 DMM or a continuity tester. If the element is open or continuity is suspect, replace the fuse with one of equal
current rating.
Fusible Links
Fuse Types
Fusible link is wire designed to melt and break continuity when excessive current is applied. It is often located between or near the battery and starter or
electrical center. Use a continuity tester or a J 39200 DMM at each end of the wire containing the fusible link in order to determine if it is broken. If
broken, it must be replaced with fusible link of the same gage size.
Repairing a Fusible Link
IMPORTANT: Fusible links cut longer than 225 mm (approx. 9 inches) will not provide sufficient overload protection. Refer to Splicing
Copper Wire Using Splice Clips.
Flat Wire Repairs
NOTE: The flat wire within the flex wiring harness is not serviceable. If an open or short exists within the flex wiring harness the complete harness
must be replaced.
H02S Wiring Repairs
