VEHICLE IDENTIFICATION
Note. This article applies to "old style" "C" & "K" Series vehicles equipped with 5.7L, 6.5L and 7.4L engines. For "new style" "C" & "K" Series vehicles equipped with 4.3L, 4.8L, 5.3L and 6.0L engines, see STARTERS -- SIERRA, SILVERADO, SUBURBAN, TAHOE, YUKON & YUKON XL article.
Vehicle model is identified by fifth character of Vehicle Identification Number (VIN). VIN is stamped on metal pad on top of left end of instrument panel, near windshield. A fifth character of "C" designates vehicle as a 2WD. A fifth character of "K" designates vehicle as a 4WD.
DESCRIPTION & OPERATION
Vehicles equipped with gasoline engines use PG260 starters. PG260 starters are not serviceable, and must be replaced as a complete assembly. Vehicles equipped with diesel engines use 28MT starters. 28MT starters may be disassembled for testing if not performing to specifications.
Battery voltage is applied at all times to ignition switch from IGN-A (40-amp) fuse, located in underhood fuse/relay center. When ignition switch is turned to START position, battery voltage is applied to CRANK (10-amp) fuse, located in instrument panel fuse block. Battery voltage continues from CRANK fuse to Park/Neutral Position (PNP) switch (A/T) or Clutch Pedal Position (CPP) switch (M/T). Current passes through PNP or CPP switch then on to coil of starter relay only when shift lever is in Park or Neutral position (A/T) or clutch pedal is depressed (M/T). Starter relay is permanently grounded at G105, located on right front side of engine block (gas) or at right rear intake manifold bolt (diesel). When starter relay is energized, it completes battery voltage circuit to starter solenoid "S" terminal. This causes solenoid plunger to move shift lever, which engages pinion with engine flywheel ring gear. Movement of plunger also closes main solenoid contacts, applying battery voltage to starter motor. (Scheme 5)
When engine starts, pinion will overrun, protecting armature from excessive speed and flywheel from damage. When ignition switch is released, plunger return spring disengages pinion.
