GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1996 🢒 GMC Suburban - 4WD 🢒 Engine 🢒 Engine Electrical 🢒 Charging System Diagnosis

Starter
  1. Visually inspect the hydrometer (built into Battery).
    2. • Green eye -- Battery is charged.
    • Dark eye -- Charge and Load Test Battery. If the Battery passes the Load Test refer to System Diagnosis.
    • Clear or light yellow eye -- Battery electrolyte is low. Replace the battery.
  2. Check that Starter Solenoid terminals S and B and Battery connections are clean and tight.
  3. Check the condition of Fuse 6 and crank fuse 8. If the fuse is open, locate and repair the source of overload and replace the fuse.
  4. Check that Grounds G101, G102, and G105 (Gasoline Engines) or Grounds G101, G102, and G105 and Ground G106 (Diesel Engines) are clean and tight.
    5. • Check for a broken (or partially broken) wire inside of the insulation which could cause system malfunction but prove good in a Continuity/Voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring for a Voltage drop with the system operational (under load).
    • Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems.

Charging System
  1. Visually inspect the hydrometer (built into the battery).
    2. • Green eye -- Battery is charged.
    • Dark eye -- Charge and Load Test Battery. If the battery passes the load test, refer to System Diagnosis.
    • Clear or light yellow eye -- Battery electrolyte is low, replace the battery.
  2. Check gauges Fuse 4 for an open. If the fuse is open, locate and repair the source of overload and replace the fuse.
  3. Check that the generator connector and generator BAT terminal are both clean and tight.
  4. Check that the battery connections are clean and tight.
  5. Check the generator belt. Adjust as required.
  6. Check fusible link for an open. If the link is open, locate and repair the source of overload and replace the link.
  7. Check that Grounds G101, G102, and G105 (Gasoline Engine) or Grounds G101, G102, G105 and G106 (Diesel Engines) are clean and tight.
    8. • Check for a broken (or partially broken) wire inside of the insulation which could cause system malfunction but prove Good in a Continuity/Voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring for a voltage drop with the system operational (under load).
    • Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems.