Feed Circuit Test

The starter feed circuit test (voltage drop method) will determine if there is excessive resistance in high-amperage feed circuit.

When performing these tests, it is important to remember that voltage drop is giving an indication of resistance between two points at which voltmeter probes are attached.

Example:  When testing resistance of positive battery cable, touch voltmeter leads to positive battery cable clamp and cable connector at starter solenoid. If you probe positive battery terminal post and cable connector at starter solenoid, you are reading combined voltage drop in positive battery cable clamp-to-terminal post connection and positive battery cable.

The following operation will require a voltmeter accurate to 1/10 (0.10) volt. Before performing tests, be certain that following procedures are accomplished:

• Battery is fully-charged and load-tested.
• Fully engage parking brake.
• If equipped with manual transmission, place gearshift selector lever in Neutral position and block clutch pedal in fully depressed position. If equipped with automatic transmission, place gearshift selector lever in Park position.
• Verify that all lamps and accessories are turned off.
• To prevent a gasoline engine from starting, remove Automatic Shut Down (ASD) relay. To prevent a diesel engine from starting, remove Fuel Pump Relay. These relays are located in Power Distribution

Center (PDC). Refer to label on PDC cover for relay location.

1. Connect positive lead of voltmeter to negative battery cable terminal post. Connect negative lead of voltmeter to negative battery cable clamp. See Fig 1.Rotate and hold ignition switch in Start position. Observe voltmeter. If voltage is detected, correct poor contact between cable clamp and terminal post.
   NOTE: Certain diesel equipped models use dual batteries. If equipped with dual battery system, procedure must be performed twice, once for each battery.
   Fig 1: Test Negative Battery Cable Connection Resistance

   Courtesy of DAIMLERCHRYSLER CORP.
2. Connect positive lead of voltmeter to positive battery terminal post. Connect negative lead of voltmeter to battery positive cable clamp. See Fig 2. Rotate and hold ignition switch in Start position. Observe voltmeter. If voltage is detected, correct poor contact between cable clamp and terminal post.
   NOTE: Certain diesel equipped models use dual batteries. If equipped with dual battery system, this procedure must be performed twice, once for each battery.
3. Connect voltmeter to measure between battery positive terminal post and starter solenoid battery terminal stud. See Fig 3. Rotate and hold ignition switch in Start position. Observe voltmeter. If reading is above 0.2 volt, clean and tighten battery cable connection at solenoid. Repeat test. If reading is still above 0.2 volt, replace faulty positive battery cable.
   NOTE: Certain diesel equipped models use dual batteries. If equipped with dual battery system, this procedure must be performed on driver side battery only.
4. Connect voltmeter to measure between negative battery terminal post and a good clean ground on engine block. See Fig 4. Rotate and hold ignition switch in Start position. Observe voltmeter. If reading is above 0.2 volt, clean and tighten negative battery cable attachment on engine block. Repeat test. If reading is still above 0.2 volt, replace faulty negative battery cable.
   NOTE: Certain diesel equipped models use dual batteries. If equipped with dual battery system, this procedure must be performed twice, once for each battery.
   Fig 2: Test Positive Battery Cable Connection Resistance

   Courtesy of DAIMLERCHRYSLER CORP.
   Fig 3: Test Positive Battery Cable

   Courtesy of DAIMLERCHRYSLER CORP.
5. Connect positive lead of voltmeter to starter housing. Connect negative lead of voltmeter to negative battery terminal post. See Fig 5. Rotate and hold ignition switch in Start position. Observe voltmeter. If reading is above 0.2 volt, correct poor starter to engine block ground contact.
   NOTE: Certain diesel equipped models use dual batteries. If equipped with dual battery system, this procedure must be performed on driver side battery only.
   Fig 4: Test Ground Circuit Resistance

   Courtesy of DAIMLERCHRYSLER CORP.
   Fig 5: Test Starter Ground

   Courtesy of DAIMLERCHRYSLER CORP.

If equipped with dual battery system (certain diesel equipped models), connect positive lead of voltmeter to positive battery cable clamp on battery located on left side of vehicle. Connect negative lead of voltmeter to positive battery terminal post on battery located on right side of vehicle. Rotate and hold ignition switch in Start position. Observe voltmeter. If reading is above 0.2 volt, clean and tighten battery cables at both batteries. Repeat test. If reading is still above 0.2 volt, replace faulty positive battery cable.

If resistance tests detect no feed circuit problems, See Starter Motor .