Starting - Service Information: Diagnosis RAM Pickup 2500

COLD CRANKING TEST

Note. See appropriate Wiring Information for complete starter wiring circuit diagrams.

Scheme 2

1. Fully charge and load-test the battery. Refer to «Diagnosis and Testing»(ref-457788-S36562289752012030200000) .
2. Connect volt-ampere tester leads (1 and 2 to the battery terminals. Connect volt-ampere tester lead (3) around the positive battery cable. See instructions provided by manufacturer of volt-ampere tester being used.
3. Place transmission in Park or Neutral with the parking brake set (depending on transmission application).
4. If equipped with manual transmission, block clutch pedal in fully depressed position.
5. Verify that all lamps and accessories are turned off.
6. To prevent a gasoline engine from starting, remove Automatic ShutDown (ASD) relay. To prevent a diesel engine from starting, remove Fuel Pump Relay. See appropriate Wiring Information for relay locations. WARNING: Attempt to start engine a few times before proceeding with following step. NOTE: A cold engine will increase starter current (amperage) draw reading, and reduce battery voltage reading.
7. Rotate and hold ignition switch in Start position. Note cranking voltage and current (amperage) draw readings shown on volt-ampere tester. If voltage reads below 9.6 volts, see starter motor diagnosis and testing. Refer to «STARTER , Diagnosis and Testing»(ref-457802-S24916842562012030200000) . If starter motor is OK, see «3.7L ENGINE - SERVICE INFORMATION»(ref-457795) , «4.7L ENGINE - SERVICE INFORMATION»(ref-457796) , «5.7L ENGINE - SERVICE INFORMATION»(ref-457797) , or «6.7L DIESEL ENGINE - SERVICE INFORMATION»(ref-457798) for further diagnosis and testing of the engine. If starter motor is not OK, replace the starter motor. Refer to «STARTER , Removal»(ref-457802-S39254669482012030200000) . See «FEED CIRCUIT TEST»(ref-457802-S01962443692012030200000) if voltage reads above 9.6 volts and current (amperage) draw reads below specifications. See «FEED CIRCUIT TEST»(ref-457802-S01962443692012030200000) if voltage reads 12.5 volts or greater and starter motor does not turn or turns very slowly.

FEED CIRCUIT TEST

Note. See appropriate Wiring Information for complete starter wiring circuit diagrams.

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 procedure requires a voltmeter accurate to 1/10 (0.10) volt. Before proceeding, be certain that the following are accomplished

1. Fully charge and load-test the battery. Refer to «Diagnosis and Testing»(ref-457788-S36562289752012030200000) .
2. Place transmission in Park or Neutral with the parking brake set (depending on transmission application).
3. If equipped with manual transmission, block clutch pedal in fully depressed position.
4. Verify that all lamps and accessories are turned off.
5. To prevent a gasoline engine from starting, remove Automatic ShutDown (ASD) relay. See appropriate Wiring Information for relay locations.

Scheme 3

Scheme 4

Scheme 5

Scheme 6

Scheme 7

1. Connect positive lead of voltmeter (1) to negative battery cable terminal post. Connect negative lead of voltmeter to negative battery cable clamp. Rotate and hold ignition switch in Start position. Observe voltmeter. If voltage is detected, correct poor contact between cable clamp and terminal post. 1 - VOLTMETER 2 - BATTERY
2. Connect positive lead of voltmeter to positive battery terminal post. Connect negative lead of voltmeter to battery positive cable clamp. Rotate and hold ignition switch in Start position. Observe voltmeter. If voltage is detected, correct poor contact between cable clamp and terminal post. 1 - BATTERY 2 - VOLTMETER 3 - STARTER MOTOR
3. Connect voltmeter (2) to measure between positive terminal post on battery (1) and the battery terminal stud on the starter solenoid (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 and repeat test. If reading is still above 0.2 volt, replace the positive battery cable. 1 - VOLTMETER 2 - BATTERY 3 - ENGINE GROUND
4. Connect voltmeter (1) to measure between negative terminal post on battery (2) and a good clean ground on engine block (3). 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 and repeat test. If reading is still above 0.2 volt, replace the negative battery cable. 1 - STARTER MOTOR 2 - BATTERY 3 - VOLTMETER NOTE: Certain diesel equipped models use dual batteries. If equipped with dual battery system, this procedure must be performed twice, once for each battery.
5. Connect positive lead of voltmeter (3) to starter housing (1). Connect negative lead of voltmeter to negative terminal post on battery (2). 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.
6. 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 and repeat test. If reading is still above 0.2 volt, replace positive battery cable.
7. If resistance tests detect no feed circuit problems, inspect and test the starter motor and solenoid. Refer to «STARTER , Diagnosis and Testing»(ref-457802-S24916842562012030200000) .

DIAGNOSIS AND TESTING

Note. This test can only be performed with starter motor removed from vehicle.

Correct starter motor operation can be confirmed by performing the following free running bench test. Refer to Specifications for starter motor service specifications.

1. Remove starter motor from vehicle. Refer to Starter Motor «Removal»(ref-457802-S39254669482012030200000) and «Installation»(ref-457802-S22328630612012030200000) .
2. Mount starter motor securely in a soft-jawed bench vise. The vise jaws should be clamped on the mounting flange of starter motor. Never clamp on starter motor by field frame.
3. Connect a suitable volt-ampere tester and a 12-volt battery to starter motor in series, and set ammeter to 100 ampere scale. See instructions provided by manufacturer of volt-ampere tester being used.
4. Install jumper wire from solenoid terminal to solenoid battery terminal. The starter motor should operate. If starter motor fails to operate, replace faulty starter motor assembly.
5. Adjust carbon pile load of tester to obtain free running test voltage. Refer to «Specifications»(ref-457802-S04621602042012030200000) for starter motor free running test voltage specifications.
6. Note reading on ammeter and compare reading to free running test maximum amperage draw. Refer to «Specifications»(ref-457802-S04621602042012030200000) for starter motor free running test maximum amperage draw specifications.
7. If ammeter reading exceeds maximum amperage draw specification, replace faulty starter motor assembly.