GMC 2003 Sierra - Manual (Page 486)

Electrical System
Add'On Electrical Equipment
Notice; Don't add anything electrical to your
vehicle unless you check with yaur dealer first
Some electrical equipment can damage your vehicle
and the damage wouldn't be covered by your
warranty. Seme add'on electrical equipment can
keep other components from working as they
should.
Your vehide has an air bag system. Before attempting
lo add anything electricai to your vehide, see
Servicing Your Air Bag-Equipped Vefjide on page 1-77
Windshieid Wiper Fuses
The Windshield wiper motor is pnoteclect by an internal
circuit breaker and a fuse. If ihe mo-tar overheats due to
heavy snow, etc,, the wiper will stop unta'i the itiator
cools. It the overload is caused by some eleclhcal
problem and not snow, etc., he sure to get it fixed.
Power Windows and Other Power
Options
Circuit hreakeis protect the pcVi-er windows and other
power accessuries. When the current load is too haavy,
the dfcuit breaker opens and closes, protecting th&
cincuil until The problem is fixed от goes away.
Fuses and Circuit Breakers
The wiring circuits In your vehicle aro protected from
short circuits by a combination of loses, circuit breakers
and fusible thermal links. This greatly reduces the
chance of fires caused by electrical problems.
Look at the silver-colored band Inside the fuse. -If the
band is broken or melted, replace the fuse. Be sure you
replace a bad fuse with a new one of the identical
stze and rating,
If you ever have a problem on the road and don't have
a spare fuse, you can borrow one that hes the same
amperage. Just pick some leature of your vehicle
that you can gel along without - like the radio or
cigarette lighter - and use its fuse, if it is the correct
amperage. ’Replace it as soon as you can.
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