Alternator not charging?

Not only did you give us good info on the correction but you included all the OEM/aftermarket tool info needed to get it updated. That is a great update.

Thanks for the info and using 2CarPros

Check two items in pic if not those then have it scanned for codes it may be a tpim module problem.

Hi bspeedo77. Welcome to the forum.

The alternator is regulated by the ECM Here is a wiring diagram and a guide so you can do some tests to see if it is a wiring issue before replacing the ECM unit.

https://www.2carpros.com/articles/how-to-check-wiring

and

https://www.2carpros.com/articles/how-to-check-a-car-alternator

You did step one already, now measure the voltages on the two small wires on the back of the alternator while the engine is running. One must have full battery voltage, the other one should have less than battery voltage, but not 0 volts. Holler back with your findings.

Alternator wiring diagram (below)

caradiodoc

Please use 2CarPros anytime, we are here to help. Please tell a friend.

Cheers

caradiodoc

Hi,

The voltage regulator is part of the power-train control module (PCM). It is not serviceable.

First, are you sure the alternator is good? Here is a link explaining how to test to see if there is power to the battery from the alt. Try this and let me know the results.

https://www.2carpros.com/articles/how-to-check-a-car-alternator

If there is no power, I would recommend (before replacing the PCM which can be expensive), remove the alternator and have it bench tested at a parts store. Most will do it at no charge. That way we can confirm which is truly the issue.

Here is a link that shows in general how to remove and replace an alternator. This is if you want to check it.

https://www.2carpros.com/articles/how-to-replace-an-alternator

Here are the directions specific to your car. The attached pictures correlate with the directions.

________________________________
2001 Dodge or Ram Truck RAM 1500 Truck 4WD V8-5.2L VIN Y
Generator Replacement
Vehicle Starting and Charging Charging System Alternator Service and Repair Procedures Generator Replacement
GENERATOR REPLACEMENT
REMOVAL

WARNING: DISCONNECT NEGATIVE CABLE FROM BATTERY BEFORE REMOVING BATTERY OUTPUT WIRE (B+ WIRE) FROM GENERATOR. FAILURE TO DO SO CAN RESULT IN INJURY OR DAMAGE TO ELECTRICAL SYSTEM.

1. Disconnect negative battery cable at battery.
2. Remove generator drive belt.

Fig.2 Remove/Install Generator
pic 1

3. In these Engines: Remove generator pivot and mounting bolts/nut (Fig. 2).
4. All Engines: Remove upper generator mounting bolt and lower mounting bolt/nut.

Fig.5 Generator Connectors - Typical Bosch
pic 2

Fig.6 Generator Connectors - Typical Denso
pic 3

5. Remove B+ terminal mounting nut at rear of generator (Fig. 5) or (Fig. 6). Disconnect terminal from generator.
6. Disconnect field wire connector at rear of generator by pushing on connector tab.
7. Remove generator from vehicle.

INSTALLATION
1. Position generator to engine and snap field wire connector into rear of generator.
2. Install B+ terminal eyelet to generator stud. Tighten mounting nut to 12 Nm (108 in. lbs.) torque.
3. Install generator mounting fasteners and tighten as follows:
- Generator mounting bolt-All these powered engines-41 Nm (30 ft. lbs.) torque.
- Generator pivot bolt/nut-All these powered engines-41 Nm (30 ft. lbs.) torque.

CAUTION:
- Never force a belt over a pulley rim using a screwdriver. The synthetic fiber of the belt can be damaged.
- When installing a serpentine accessory drive belt, the belt MUST be routed correctly. The water pump will be rotating in the wrong direction if the belt is installed incorrectly, causing the engine to overheat. Refer to belt routing label in engine compartment.

4. Install generator drive belt.
5. Install negative battery cable(s) to battery(s).

____________________________

There is one other thing. There is an alternator cartridge fuse in the power distribution box. It is a 140 amp fuse. This fuse has a color-coded plastic housing and a clear plastic fuse conductor inspection cover like other cartridge fuses, but has a higher current rating and is connected and secured with screws instead of being pushed onto male spade-type terminals. The generator cartridge fuse cannot be repaired and, if faulty or damaged, it must be replaced. I doubt this is the cause, but anything is possible.

Let me know if any of this helps or if you have other questions.

Take care,
Joe

Good afternoon,

I attached a wiring diagram for you to view.

Make sure you have power from the battery to the big stud.

https://www.2carpros.com/articles/how-to-check-a-car-alternator

I attached a flow chart for you to follow to determine the failure.

Roy

The other 2 wires go to the ECM. The ECM turns the alternator on and off based on electrical load.

The following procedures may be used to diagnose the charging system if:
the check gauges lamp (if equipped) is illuminated with the engine running
the voltmeter (if equipped) does not register properly
an undercharged or overcharged battery condition occurs.

Remember that an undercharged battery is often caused by:
accessories being left on with the engine not running
a faulty or improperly adjusted switch that allows a lamp to stay on. Refer to Ignition-Off Draw Test in Battery for more information.

INSPECTION
The Powertrain Control Module (PCM) monitors critical input and output circuits of the charging system, making sure they are operational. A Diagnostic Trouble Code (DTC) is assigned to each input and output circuit monitored by the On-Board Diagnostic (OBD) system. Some charging system circuits are checked continuously, and some are checked only under certain conditions.

Refer to Diagnostic Trouble Codes in; Powertrain Control Module; Electronic Control Modules for more DTC information. This will include a complete list of DTC's including DTC's for the charging system.

To perform a complete test of the charging system, refer to the appropriate Powertrain Diagnostic Procedures and the DRB III scan tool. Perform the following inspections before attaching the scan tool.
1. Inspect the battery condition. Refer to Battery for procedures.
2. Inspect condition of battery cable terminals, battery posts, connections at engine block, starter solenoid and relay. They should be clean and tight. Repair as required.
3. Inspect all fuses in both the fuseblock and Power Distribution Center (PDC) for tightness in receptacles. They should be properly installed and tight. Repair or replace as required.
4. Inspect generator mounting bolts for tightness. Replace or tighten bolts if required. Refer to the Generator Removal/Installation for torque specifications.
5. Inspect generator drive belt condition and tension. Tighten or replace belt as required. Refer to Belt Tension Specifications in, Cooling System.
6. Inspect automatic belt tensioner (if equipped).
7. Inspect generator electrical connections at generator field, battery output, and ground terminal (if equipped). Also check generator ground wire connection at engine (if equipped). They should all be clean and tight. Repair as required.

Frank, I would remove the alternator and take it to a parts store and have them test it. They have the equipment to run it on a test bench. It is a free service.

Then you can be sure if it is good or bad.

Roy

Check that the 140 amp fuse for the alternator is good as well. Check fuse 12 (10A) for the lights and DLC failure.

Hi, use a digital multimeter across battery posts, everything turned off. The generic spec for a fully charged battery is around 12.6 volts. With engine running, take second reading across battery posts, the second should be higher than the first, if charging system is working.

The bat terminal at the alternator, black wire with gray tracer, should be hot even with everything turned off.

You may have to check to see if there is a trouble code for the charging system. Let us know what you find.

Check the generator fuse, also check voltage to the fuse.