GMC 4000 Series Service Manual page 545

Sec. 12
______________________ G M C S E R V I C E M A N U A L
Page 534
CHASSIS ELECTRICAL A N D INSTRUMENTS
KEEP ALL WIRING CONNECTIONS
CLEAN AND TIGHT
DO NOT REPLACE FUSIBLE LINKS WITH
WIRE OF LARGER GAUGE OR LENGTH
DISCONNECT NEGATIVE BATTERY CABLE
FROM BATTERY BEFORE REPLACING
INSTRUMENTS OR GAUGES