Replacing the heater core in a 2015 Ram 5500 is a complex task that requires significant disassembly of the vehicle's interior. This process involves removing the dashboard and other components to access the heater core located behind the firewall. Here's a comprehensive guide to help you through this challenging repair.

Preparation

Before starting the heater core replacement, gather the following:

  • New heater core
  • Coolant
  • Basic hand tools (screwdrivers, socket set, pliers)
  • Torx bits
  • Penetrating oil
  • Drain pan
  • Safety equipment (gloves, safety glasses)

Disconnect the battery and drain about 1 gallon of coolant from the system before beginning work.

Dashboard Removal

Removing the dashboard is the most time-consuming part of this job:

  • Remove the steering column shroud and lower dash panels
  • Disconnect all electrical connectors behind the dash
  • Remove the instrument cluster and radio
  • Unbolt the dashboard from the firewall and carefully pull it away

Be extremely cautious with airbag components and wiring during this process.

Accessing the Heater Core

Once the dashboard is out of the way:

  • Locate the heater box behind the firewall
  • Remove the heater box cover
  • Disconnect and remove the old heater core
  • Clean the heater box thoroughly before installation

Installation

Installing the new heater core is essentially the reverse of removal:

  • Carefully place the new heater core in the heater box
  • Reconnect all hoses and ensure proper seating
  • Reassemble the heater box
  • Refill the coolant system and check for leaks

Reassembly

Putting everything back together requires patience and attention to detail:

  • Carefully reposition the dashboard
  • Reconnect all electrical connectors
  • Reinstall all removed components in reverse order
  • Double-check all connections before reconnecting the battery

Additional Considerations

While the heater core is exposed, consider replacing these components:

  • Evaporator core
  • Blend door actuators
  • Expansion valve

These parts are difficult to access, so replacing them now can save future labor.

Tips for Success

  • Label all connectors and bolts during disassembly
  • Take photos at each step for reference
  • Use a proper coolant mixture specified for your Ram 5500
  • Perform a thorough leak check before fully reassembling the interior

Replacing a heater core in a Ram 5500 is a significant undertaking that can take 8-12 hours for an experienced mechanic. If you're not confident in your abilities, it's best to leave this job to a professional to ensure proper installation and avoid potential damage to other vehicle systems.