How to Change the Alternator on a Dodge 2500 Diesel

by Gregory Crews
New car petrol engines image by Christopher Dodge from

The Dodge 2500 Ram pickup truck is a high-powered truck made for work. The truck uses two batteries to power the components and the Cummins turbo diesel. The alternator is responsible for charging the batteries and alternating the electric current to a current the truck can use. The alternator is accessible and replacing it should only take a matter of minutes.

Step 1

Ensure the truck is parked on a flat and level surface. Open the hood for access to the engine bay.

Step 2

Disconnect both batteries by disconnecting the positive and negative terminals. This will isolate the electrical power.

Step 3

Locate the alternator at the top of the engine toward the passenger side of the engine. Pull the belt off the alternator by inserting a socket wrench into the tensioner pulley directly below the alternator. The tensioner pulley has a square slot that will fit the head of the socket wrench. Push the tensioner down and this will loosen the belt. Pull the belt off the pulley.

Step 4

Pull the wires off the back of the alternator. There will be two wiring harness attached at the back. They can be pulled off the connectors.

Step 5

Unbolt the alternator by unscrewing the two bolts holding the alternator to the mounting bracket. Pull the alternator away from the engine compartment.

Step 6

Bolt the new alternator to the mounting bracket. Ensure both both bolts are tightened with the socket wrench.

Step 7

Connect the wires to the back of the alternator. Push them in until they lock in place.

Step 8

Push the tensioner pulley down to ensure the belt can go over the alternator pulley. Slowly allow the tensioner to rise back to its original position. This will tighten the belt.

Step 9

Connect both the batteries. Ensure the positive cable is hooked to the positive terminal. The terminal is identified with a "+" symbol above it.

Start the truck to allow it to idle. The truck needs to run for at least 15 minutes to ensure the batteries get a full charge. Shut the truck down for at least an hour. Attempt to start later to ensure the battery is holding a charge.


  • Inquire if there is a core charge when purchasing the alternator. This will require returning the old alternator to receive a deposit made when purchasing the new alternator.
  • Most automotive-parts stores can perform a bench test on the alternator to determine if it needs replacing. You can drive the truck to the store or take the alternator off and bring it in. They will tell you if the alternator is bad.


  • Use caution when working around the electrical system. Isolate the electrical power to prevent electrical shock.

Items you will need

  • Socket wrench
  • Socket set
  • New alternator

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