Main Relay

Replace the main relay (also called the power distribution center relay or fuel pump relay) on the 2005 Dodge Viper, located in the power distribution center under the hood.

Warnings

Tools required

Parts

• Main relay (Power Distribution Center relay) × 1 — Use OEM specification - verify relay type from PDC cover diagram

Preparation

1. Park vehicle on level surface and turn ignition OFF
2. Allow engine to cool if recently operated
3. Open hood and secure with prop rod

Procedure

1. 1

   Disconnect Battery Negative Terminal
   Locate the battery in the engine compartment (passenger side). Loosen the negative terminal bolt using a 10mm socket and disconnect the negative cable. Secure cable away from terminal post. Loosen the negative terminal bolt using a 10mm socket and disconnect the negative cable. Secure cable away from terminal post.
2. 2

   Locate Power Distribution Center
   The Power Distribution Center (PDC) is located in the engine compartment (verify side against factory diagram; on the 2005 Viper it is typically on the passenger side inner fender area near the battery). It is a black plastic box with multiple relays and fuses visible when the cover is removed. It is a black plastic box with multiple relays and fuses visible when the cover is removed.
3. 3

   Remove PDC Cover
   Release the cover latches on the Power Distribution Center. The cover typically has 2 snap-latch points on the sides. Lift the cover up and off. Inspect the relay diagram printed on the underside of the cover to identify the main relay position.
   ℹ️The main relay may be labeled as 'Fuel Pump Relay', 'ASD Relay' (Auto Shutdown Relay), or similar depending on circuit function. Verify position from diagram.
4. 4

   Identify Main Relay
   Using the diagram on the PDC cover, locate the main relay. On the 2005 Viper, the ASD relay (Auto Shutdown Relay) is the primary relay controlling fuel pump and ignition coil power. It is typically a standard automotive relay with 4 or 5 pins in a square configuration.
5. 5

   Remove Main Relay
   Grip the relay body firmly and pull straight up with steady even pressure. If the relay is difficult to remove, use a flathead screwdriver or relay puller to carefully pry under the relay edges, alternating sides to avoid bending pins. Rock the relay gently while pulling to break it free from the socket.
6. 6

   Inspect Relay Socket
   Examine the relay socket terminals for corrosion, heat damage, or bent contacts. Clean any corrosion with electrical contact cleaner and a small brush. If terminals are damaged or burnt, the entire PDC may require replacement. Check for moisture intrusion in the PDC box.
7. 7

   Install New Main Relay
   Apply a small amount of dielectric grease to the relay pins if desired (optional but recommended for corrosion protection). Align the new relay with the socket, ensuring correct orientation (relays are keyed and will only fit one way). Press the relay firmly into the socket until it is fully seated and flush with surrounding relays.
8. 8

   Reinstall PDC Cover
   Position the PDC cover over the box, ensuring no wires are pinched. Press down firmly on both latch points until the cover snaps securely into place. Verify the cover is fully seated.
9. 9

   Reconnect Battery Negative Terminal
   Reconnect the negative cable to the negative terminal post at the battery in the engine compartment. Tighten the terminal bolt to specification using a 10mm socket and torque wrench.

Reassembly

1. Ensure PDC cover is properly latched to prevent moisture intrusion
2. Verify battery terminal is clean and tight before operation

Verification

• Turn ignition to ON position (do not start engine) and listen for fuel pump activation for 2-3 seconds
• Attempt to start the engine - it should crank and start normally
• Check for any warning lights on the instrument cluster related to fuel system or powertrain
• Verify all electrical systems function normally (radio, windows, etc.) after battery reconnection
• If engine starts and runs normally with fuel pump audible during key-on, relay replacement is successful

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