Where is the ASD relay on a 97 RAM?

The ASD relay on a 1997 RAM is located in the engine bay, inside the under-hood fuse/relay box (the Power Distribution Center). It’s typically found on the driver's side near the battery, and the lid of the box has a diagram labeling the ASD relay.

What the ASD relay does

The Auto Shutdown (ASD) relay is controlled by the Powertrain Control Module (PCM). When the key is ON, the ASD relay feeds power to critical ignition components and the fuel injectors. If the PCM detects a fault, it can shut off power to these circuits, preventing engine start or running. A faulty ASD relay can cause no-start conditions, intermittent starting, or a stall with no clear warning.

Where to locate it on a 1997 RAM

In most 1997 Dodge Ram models with the 5.2L or 5.9L V8, the ASD relay is in the main under-hood fuse/relay box, commonly referred to as the Power Distribution Center (PDC). This box is a black plastic block mounted in the engine compartment, typically on the driver's side near the battery. The lid usually includes a diagram that marks the ASD relay position.

Before you begin the search, it helps to have the PDC lid and its diagram in hand, so you can match the label to the exact relay position. If your truck has a nonstandard configuration or aftermarket wiring, consult the factory wiring diagram for your exact engine and trim.

Steps to locate the ASD relay are straightforward, but the exact position can vary slightly by model year and engine type.

1. Open the hood and locate the Power Distribution Center (PDC) under the hood. It’s a black plastic box usually on the driver's side of the engine bay near the battery.


2. Remove the PDC cover to expose the relay connections.


3. Inspect the relays for a label or marking that reads "ASD" or "Auto Shutdown." If labeled, this is the ASD relay position.


4. If there is no obvious ASD label, check the diagram on the inside of the PDC lid or the accompanying fuse/relay map to identify the ASD slot.


5. If you still can’t identify the ASD relay, refer to the owner’s manual or a service manual for your exact engine (5.2L or 5.9L) to locate the correct slot.


6. Reinstall the cover and close the PDC once you’ve identified the ASD relay.

In most cases, the ASD relay sits in the primary under-hood fuse/relay block. If you cannot find an ASD label or the diagram is unclear, the relay may be in a different slot or the vehicle may use a non-typical labeling system for that year. When in doubt, consult a service manual for your specific RAM configuration.

Testing and replacing the ASD relay

Testing the ASD relay involves verifying that it receives control signals from the PCM and that it provides power to the ignition and fuel systems when commanded. If the relay isn’t energizing or if you’re seeing symptom-driven no-starts, swapping in a known-good relay of the same type is a common diagnostic step.

• First, identify the ASD relay in the PDC by label, or by using the diagram on the lid. Ensure the vehicle is off before removing the relay.


• With the ignition ON, use a test light or multimeter to check for 12V at the ASD relay input terminal. If there is no voltage, the issue may be wiring or PCM control rather than the relay itself.


• Swap the ASD relay with another relay of the same amperage and function (for example, a relay in a known-good slot such as the horn or cooling fan relay) to see if the engine starts or runs, which helps confirm a bad ASD relay.


• If power is present on the input but you still have ignition/fuel issues, the problem may lie in the PCM, wiring harness, or sensors rather than the relay.


• Install a new, identical-spec ASD relay if testing indicates failure, then recheck engine starting and operation.

Testing results should be interpreted with care: a faulty ASD relay can mimic other no-start problems, and intermittent starts can point to wiring or PCM issues rather than a single relay failure.

Summary

For a 1997 RAM, the ASD relay is normally inside the engine bay’s Power Distribution Center (the main under-hood fuse/relay box), typically on the driver's side near the battery. Look for a relay labeled "ASD" or consult the lid diagram. If you’re troubleshooting a no-start issue, testing or swapping the ASD relay with a known-good unit is a common diagnostic step, but remember that wiring, sensors, and the PCM can also contribute to similar symptoms.