Main Relay

Remove and replace the main relay (also called ASD relay or automatic shutdown relay) which controls power to the fuel pump and ignition system on the 1992 Dodge Viper RT/10.

Warnings

Tools required

Parts

• Main relay (ASD relay) × 1 — Mopar 56028129 or equivalent

Preparation

1. Park vehicle on level ground and engage parking brake
2. Turn ignition to OFF position and remove key
3. Open hood and secure with prop rod

Procedure

1. 1

   Disconnect battery negative terminal
   Locate the battery in the engine compartment. Using a 10mm socket, loosen the negative battery terminal bolt and remove the cable from the battery post. Using a 10mm socket, loosen the negative battery terminal bolt and remove the cable from the battery post. Secure the cable away from the battery to prevent accidental reconnection.
   Torque spec

   Battery Terminal Bolts6 Nm (4 lb-ft)
2. 2

   Locate the Power Distribution Center
   The Power Distribution Center (PDC) is located in the engine compartment on the driver's side inner fender, near the firewall. It is a black rectangular box with a removable cover. The main relay is housed inside this center along with other relays and fuses.
3. 3

   Remove PDC cover
   Release the cover latches on the sides of the Power Distribution Center by pressing the tabs inward or lifting the latch mechanism (depending on cover design). Lift the cover straight up to remove it. The underside of the cover typically has a relay and fuse location diagram.
4. 4

   Identify the main relay
   Locate the main relay (ASD relay) using the diagram on the underside of the PDC cover. The relay is typically in position marked 'ASD' or 'Main Relay' and is a standard automotive relay with 4 or 5 pins. Note the orientation of the relay before removal.
5. 5

   Remove the main relay
   Grip the relay body firmly and pull straight up with steady pressure to remove it from its socket. The relay has blade-type terminals that friction-fit into the PDC socket. If the relay is difficult to remove, use a small flathead screwdriver to gently pry upward while pulling, being careful not to damage the socket terminals.
6. 6

   Inspect relay socket and terminals
   Examine the relay socket in the PDC for corrosion, burnt terminals, or damage. Check that all socket pins are present and not bent. If corrosion is present, clean the socket terminals with electrical contact cleaner. Inspect the terminals on the old relay for signs of overheating (discoloration or melting).
7. 7

   Install new main relay
   Align the new relay with the socket, matching the orientation of the original relay. The relay will only fit one way due to the blade terminal arrangement. Push the relay firmly into the socket until it is fully seated and the relay body sits flush against the PDC.
8. 8

   Reinstall PDC cover
   Position the PDC cover over the Power Distribution Center and press down evenly until the latches engage on both sides. Ensure the cover is fully seated and secured.
9. 9

   Reconnect battery negative terminal
   Return to the battery location in the engine compartment. Position the negative cable on the battery post and tighten the terminal bolt using a 10mm socket to the specified torque.
   Torque spec

   Battery Terminal Bolts6 Nm (4 lb-ft)

Reassembly

1. Ensure PDC cover is fully latched and secured
2. Verify battery terminal is tight and will not move when wiggled by hand

Verification

• Turn ignition key to ON position (do not start). Listen for the fuel pump to run for approximately 2 seconds, then shut off. This confirms the main relay is providing power to the fuel pump.
• Start the engine and verify it runs normally without hesitation or stalling.
• Check that no warning lights remain illuminated on the instrument cluster after startup.
• Turn engine off and restart to confirm reliable operation.

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

Chasing one of these codes and not sure which part is guilty? Ask a master mechanic about YOUR car →

More procedures for this vehicle