Visual Inspection
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2003 GMC Sonoma, 2003 GMC Safari, 2003 GMC Jimmy, 2003 Chevrolet S10 Pickup, and 2003 Chevrolet Blazer. However, it is still accessible from the selected car via links, so may be relevant.
Visually inspect all electrical wiring. Look for chafed, stretched, cut or pinched wiring. Ensure electrical connectors fit tightly and are not corroded. Ensure vacuum hoses are properly routed and not pinched or cut. If necessary, see appropriate VACUUM DIAGRAMS in VACUUM DIAGRAMS - ASTRO & SAFARI article or VACUUM DIAGRAMS in VACUUM DIAGRAMS - BLAZER, JIMMY CANADIAN, SONOMA & S10 PICKUP article to verify routing and connections. Inspect air induction system for possible vacuum leaks.