How to Change 2004 Dodge Ram 1500 5.7L Alternator

• This how-to describes the process of removing a faulty alternator and replacing it with another of the same kind. The instructions are specific to 2004 Dodge Ram 5.7-liter models.

To remove a faulty alternator and replace it with another of the same kind, follow all instructions below. The directions provide detailed guidance on how to take the alternator off and put a new generator back in its place.

Alternator Description

An alternator is an electric generator that produces and alternating current (AC). When the vehicle is running, the alternator relies on mechanical energy to generate electrical energy. The alternator on the 2004 Dodge Ram 1500 5.7-liter is belt-driven by the engine. It uses a serpentine type drive belt to rotate the alternator pulley. As the energized rotor starts spinning inside the generator, the spinning magnetic field produces an electric charge into the windings of the stator coil.

The stator winding connections send the alternating current to three positive and three negative diodes for rectification. The rectifier coverts the alternating current to direct current (DC). This direct current or rectified current is sent to the truck’s electrical system through the alternator’s battery terminal. 

Externally, alternators appear similar in every detail. However, internally, generators have different output ratings. The 2004 Dodge Ram pickups come in several models and engine sizes, and with different alternators. When it’s time to swap the old alternator for a new one, be certain to switch it with a generator that has the same output ratings.

Generator Ratings – 5.7L

These alternator output ratings are specific to 2004, 5.7-liter models only. Although, the 5.9L diesel engine alternators are interchangeable, same alternator and same part number as 5.7L models.

How to Change Alternator

Before you remove the alternator and replace it with another of the same kind, understand that the removal and installation instructions herein are specific to 2004 Dodge Rams with 5.7L gasoline engines. 

Remove

Caution: unbolt and disconnect the negative battery cable before removing the alternator output wire (B+) from generator. Failure to do so can result in sever damage to the vehicle’s electrical system, and injury to one’s self.

1. Unfasten the negative battery cable by lifting it off the batteries negative lead terminal.
2. Remove the serpentine belt. If the belt is worn-out, now’s a good time to put in a new replacement belt.
3. Unsnap the insulator cap from alternator B+ output terminal, see illustration 1.
   

   Illustration 1: (1) Alternator. (2) B+ Nut. (3) Plastic Insulator Cap. (4) Field Wire Connector.

   
   
4. See illustration 1. Take off the mounting nut from terminal B+ on the back of alternator, then remove that connected terminal from alternator..
5. See illustration 1. Take off the field wire connector from the back of alternator by pressing on the connector tab.
6. See illustration 2. Take off the alternator support bracket, bolts and nuts, then pull out support bracket.
   

   Illustration 2. (1) Generator. (2) Support Bracket. (3) Bracket nuts. (4) Bracket Bolt.

7. See illustration 3. Remove both alternator mounting bolts.
   

   Illustration 3. (1) Mounting Bolt. (2) Generator. (3) Mounting Stud / Bolt

8. Remove alternator from the engine bay. 

Replace

Before you replace the alternator with another, be certain the serpentine accessory drive belt is routed the correct way. If you route the drive belt  incorrectly, it could cause the water pump to rotate backwards and the vehicle will overheat. Refer to belt routing schematics, below.

Accessory Drive Belt Routing: (1) Generator. (2) Idler Pulley. (3) Power Steering Pump. (4) A/C Compressor. (5) Crankshaft. (6) Belt Tensioner. (7) Water Pump.

1. Put new generator in engine and re-install the two mounting bolts. Tighten bolts to 41 N·m (30 ft. lbs.) of torque.
2. Position support bracket to front of alternator and re-install the bolts and nuts. Tighten the generator support bracket bot/nuts to 41 N·m (30 ft. lbs.) of torque.
3. Put the snap field wire connector back into the rear of alternator.
4. Re-install B+ terminal to alternator output stud then tighten the mounting nut to 12 N·m (9 ft. lbs.) of torque.
5. Install alternator drive belt. Do not use a screwdriver to force the drive belt onto the pulley as it can damage the belt fibers. Refer to the accessory drive belt routing schematic to be certain you are installing it correctly.
6. Remember to place the negative battery cable back onto the battery lead terminal.  

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