Relay - Generic

This procedure covers the removal and replacement of a generic relay in the 2007 Ram 3500 with 5.9L Cummins diesel engine.

Warnings

Tools required

Parts

• Replacement relay × 1 — Match original relay amperage and pin configuration

Preparation

1. Identify the specific relay requiring replacement by consulting the relay diagram on the underside of the PDC cover or in the owner's manual
2. Note the relay location, number, and function before removal
3. Ensure ignition is in the OFF position and key is removed
4. Disconnect the negative battery cable and wait 2 minutes for system capacitors to discharge
5. Protect the fender with a cover if working in the engine compartment

Procedure

1. 1

   Access the relay location
   For PDC relays: Release the two tabs on the Power Distribution Center cover located near the battery and remove the cover. For additional relays: Additional relays on this truck are consolidated in the under-hood Power Distribution Center (PDC/TIPM) near the battery rather than a separate firewall module; refer to the PDC cover diagram for their locations. For junction block relays: Remove the left kick panel by pulling it away from the retaining clips.
2. 2

   Identify the target relay
   Locate the specific relay using the diagram on the PDC cover or in the service manual. Common relays include fuel pump/lift pump relay, starter relay, intake air heater (grid heater) relays, A/C compressor relay, and various lighting relays. Verify you have identified the correct relay by checking the relay number and function label.
3. 3

   Test the existing relay (optional)
   If diagnosing a potential relay failure, use a digital multimeter to test the relay. Check for continuity between the coil terminals and across the switch terminals when energized. A relay puller tool or needle-nose pliers can be used to remove the relay for bench testing.
4. 4

   Remove the relay
   Grasp the relay firmly and pull straight up with steady pressure to remove it from the socket. If the relay is difficult to remove, use a relay puller tool or carefully work needle-nose pliers under opposite edges of the relay base, rocking gently while pulling upward. Do not twist or bend the relay during removal to avoid damaging the socket terminals.
5. 5

   Inspect the relay socket
   Examine the relay socket for corrosion, burned terminals, or damage. Clean any corrosion with electrical contact cleaner and a small wire brush. If terminals are burned or damaged, the entire relay center or power distribution module may require replacement.
6. 6

   Verify replacement relay specifications
   Compare the new relay to the old relay. Verify matching amperage rating, voltage rating, pin configuration, and physical dimensions. The relay amperage and voltage should be marked on the relay body. Installing an incorrect relay can cause electrical system damage or component failure.
7. 7

   Install the new relay
   Align the relay pins with the socket terminals, ensuring correct orientation by matching any alignment tabs or notches. Press the relay firmly into the socket until it seats fully and is flush with surrounding relays. The relay should snap into place with even resistance.
8. 8

   Reinstall covers and reconnect battery
   Replace the PDC cover, kick panel, or IPM access panel as applicable. Ensure all cover tabs are fully engaged. Reconnect the negative battery cable to the battery terminal and tighten securely.

Reassembly

1. Ensure all relay box covers are properly seated and latched to prevent water intrusion
2. Verify no tools or parts were left in the engine compartment or interior
3. Double-check that the correct relay was installed in the correct position

Verification

• Turn the ignition to the ON position without starting the engine and verify no warning lights are illuminated on the instrument cluster
• Start the engine and verify it starts normally without hesitation
• Test the function controlled by the replaced relay (lights, fuel pump, A/C, etc.) to confirm proper operation
• Listen for any abnormal clicking or buzzing from the relay location that might indicate a faulty relay or electrical issue
• If the relay was for the glow plug system on the Cummins diesel, verify the wait-to-start light functions properly and the engine starts smoothly in cold conditions

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