Chevrolet 4500 HD 2023 Manual page 284

When Slow-blow Fuses Blow Out
Slow-blow fuses protect the electrical
circuits, and they are installed so that they
can be quickly replaced if there is a
malfunction.
If an overload exists in the circuit from the
battery, the slow-blow fuse will blow out
before the wiring harness is damaged to
protect the electrical circuitry.
Inspection
When the headlights and other devices in
the electrical system do not work, but there
is no problem with the fuses, check the
slow-blow fuse.
The slow-blow fuse is blown if it looks like
the illustration. Immediately contact the
nearest dealer.
Vehicle Care
Warning
Always use fuses specified by the dealer
when replacing the slow-blow fuse. Using
fuses with a rating other than that
specified, or using wire or tin foil, etc.,
could result in fire or damage.
If the new fuses blow right away and the
cause is unknown, contact your dealer.
Do not inspect or replace fuses when the
starter switch is in the ON position.
Doing so may lead to an accident.
When inspecting fuses, be sure to park
the vehicle on flat, level ground and
apply chocks to the wheels.
It is not necessary to open or close the
cover unless trouble is found.
The relay box structure makes it difficult for
water to enter. If you should spill water or a
beverage of the cover, however, wipe it off
before opening the cover.
The area around the cover will get warm
when the vehicle is being driven, but this is
not abnormal.
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