Dodge Ram 1500 ASD Relay Location, Symptoms & Test Guides

If your Dodge Ram 1500 is turning over but won’t start, or it sputters to life only to die a few seconds later, you are likely in the middle of a very frustrating diagnostic puzzle. One of the most common—and most confusing—culprits is a small component called the Automatic Shutdown (ASD) relay.

The ASD relay is a critical, computer-controlled “master switch” for your engine’s entire management system. When it fails, it doesn’t just take out one component; it cuts power to everything the engine needs to run, making diagnosis difficult.

The biggest challenge for many owners is simply finding it. The location, and indeed the very existence of a serviceable ASD relay, changes drastically depending on your truck’s model year.

This guide provides a comprehensive, generation-by-generation breakdown of the Dodge Ram 1500 ASD relay location, what it does, symptoms of failure, and how to test it.

What is the Auto Shutdown (ASD) Relay and What Does It Do?

Think of the Auto Shutdown (ASD) relay as the main power switch for your engine’s core components. It is not a simple relay but a vital component of the engine management system, controlled directly by the Powertrain Control Module (PCM).

Its main function is to supply battery voltage to the most critical engine systems, but only when the PCM confirms it is safe and necessary to do so.

When the ASD relay is activated, it provides 12-volt power to:

Fuel Injectors
Ignition Coils
The Fuel Pump (or the fuel pump relay’s control circuit)
The Alternator Field
Oxygen Sensor Heaters (in some models)

The Two-Stage Operational Sequence

Understanding how the ASD relay works is key to diagnosing it. It does not stay on all the time.

Key-On (Prime): When you first turn the ignition key to the “ON” (or “RUN”) position, the PCM energizes the ASD relay for approximately one to two seconds. This “primes” the fuel system, building pressure. If the PCM does not see a “crank” signal after this, it de-energizes the relay.
Cranking/Engine-On (Run): As you turn the key to “START” and the engine begins to crank, the PCM receives a signal from the Crankshaft Position Sensor. Once the PCM confirms the engine is rotating, it energizes the ASD relay again, and keeps it energized as long as the engine is running.

The ASD Relay as a Safety Feature

This system is not just for engine control; it is a critical safety feature. If the engine stalls, or more importantly, if the vehicle is in a collision and the airbags deploy, the PCM will instantly de-energize the ASD relay.

This action immediately kills power to the ignition coils (stopping spark) and the fuel injectors/fuel pump (stopping fuel flow), which is designed to prevent a potential fire from leaking fuel.

Dodge Ram 1500 ASD Relay Location by Generation (1994-2025)

This is the primary source of confusion for most owners, as the location and serviceability of the ASD relay differ completely by generation. A 2nd Gen owner has a simple plug-in relay, while a 4th Gen owner is searching for a part that doesn’t exist in a serviceable form.

The table below provides the quickest answer. Find your model year and see the location.

Model Year (Generation)	Location	Relay Label/ID	Serviceable?
2019 – 2025 (5th Gen)	Under-hood Power Distribution Center (PDC)	K16	Yes (Plug-in)
2009 – 2018 (4th Gen)	Soldered to TIPM circuit board	(N/A)	No
2006 – 2008 (3rd Gen)	Under-hood Integrated Power Module (IPM)	Relay 5	Yes (Plug-in)
2002 – 2005 (3rd Gen)	Under-hood Integrated Power Module (IPM)	R4	Yes (Plug-in)
1994 – 2001 (2nd Gen)	Under-hood Power Distribution Center (PDC)	Relay 1	Yes (Plug-in)

A. 5th Gen (2019 – 2025) ASD Relay Location

For modern 5th Generation Ram 1500s, Chrysler (Stellantis) returned to a more logical, serviceable design.

Location: The ASD relay is a standard plug-in relay located in the main under-hood fuse box, officially called the Power Distribution Center (PDC). This is the large black box in the engine compartment, usually near the battery.
Label: Inside the PDC, the relay is identified on the assignment list as K16 for “Automatic Shutdown (ASD)”.

B. 4th Gen (2009 – 2018): The “Missing” Relay & TIPM Warning

This is, by far, the most problematic generation for this issue. If you are searching for a plug-in ASD relay on your 2009-2018 Ram 1500, you can stop looking.

You will not find a user-serviceable, plug-in ASD relay on a 4th Gen Ram 1500.

Location: The ASD function is integrated directly into the Totally Integrated Power Module (TIPM), which is the official name for the entire fuse box and control module assembly.
The Real Problem: The components controlled by the ASD logic, specifically the fuel pump relay, are notoriously faulty in this generation. This small relay is soldered directly to one of the TIPM’s internal circuit boards and cannot be serviced.
Symptoms of this Flaw: This defect is the cause of the infamous 4th Gen “crank-no-start” condition. Conversely, the relay can also stick in the on position, causing the fuel pump to run continuously after the truck is shut off, resulting in a dead battery (a “parasitic drain”).
Solution: This flaw is so common that an entire aftermarket industry exists to solve it. Solutions range from installing an external bypass kit to replacing or rebuilding the entire TIPM. For more information on this specific issue, owners can consult resources from TIPM solution specialists. For a full breakdown of this issue, see our guide: (https://truckguider.com/dodge-ram-tipm-guide).

C. 3rd Gen (2002 – 2008) ASD Relay Location

For 3rd Generation Rams, the ASD relay is a standard plug-in relay, but its label changes mid-generation.

Location: The relay is located in the under-hood fuse box, called the Integrated Power Module (IPM), which is located in the engine compartment near the battery.
Labels (The Mid-Gen Split):
- 2002-2005 Models: On the fuse/relay diagram, the ASD relay is labeled R4 (Auto Shut Down (Gasoline) relay).
- 2006-2008 Models: On the fuse/relay diagram, the ASD relay is labeled Relay 5 (Auto Shut Down (ASD) Relay).

D. 2nd Gen (1994 – 2001) ASD Relay Location

The 2nd Generation Ram 1500 features the most straightforward design.

Location: The ASD relay is a plug-in relay located in the Power Distribution Center (PDC), the main fuse box under the hood.
Label: In the PDC diagrams for this generation, the ASD relay is clearly identified as Relay 1.

Top 4 Symptoms of a Bad ASD Relay

Because the ASD relay powers the engine’s “run” systems, its failure leads to very distinct and sudden symptoms.

1. Engine Starts and Immediately Stalls

This is the single most common symptom of a failing ASD relay.

This happens because the 1-2 second “prime” sequence works (see Section 2), allowing the engine to fire. However, when the PCM tries to switch the relay to “run” mode, the faulty relay fails to stay energized. The moment the prime-cycle power is cut, the engine loses both spark and fuel and stalls.

2. Engine Cranks But Will Not Start

This is a classic “crank-no-start” condition. The starter motor will turn the engine over (you’ll hear “rer-rer-rer”), but the engine will never fire.

This occurs because the ASD relay is not activating at all. As a result, there is no power to the ignition coils (no spark) and no power to the fuel injectors (no fuel), making combustion impossible.

3. Check Engine Light (CEL) is On

The PCM is intelligent. It monitors the output of the ASD relay circuit. If the PCM commands the relay “on” but does not detect the expected 12-volt output, it correctly identifies a fault. It will then store a Diagnostic Trouble Code (DTC) and illuminate the Check Engine Light.

4. Engine Does Not Crank at All

In some cases, a failed ASD relay can cause a “no-crank” condition where the engine does not even turn over. While the ASD relay does not directly control the starter, its failure is part of a system-wide electrical logic. The PCM may be programmed to prevent starter engagement if it detects a critical fault in the ASD circuit.

Confirming the Issue: Common ASD Relay Trouble Codes (DTCs)

Before you replace any parts, the first step in any modern diagnosis is to scan the vehicle for Diagnostic Trouble Codes (DTCs) with an OBD-II scanner. A code can often point you directly to the problem circuit.

However, a DTC often points to the circuit, not necessarily the component. For example, a code for the ASD relay circuit could be triggered by a bad relay, but it could also be triggered by a shorted ignition coil or fuel injector on that circuit, which in turn damages the relay or blows its fuse.

A real-world example is code P0688. On a Ram 5.7L, this code (“ASD / Main Sense Circuit”) was traced back to a cracked ignition coil on cylinder 7. The coil was shorting to the engine block, causing the ASD fuse (Fuse 52) to blow repeatedly, which then logged the P0688 code. The new relay kept failing until the root cause (the bad coil) was found.

DTC Code	Description	What It Likely Means
P0688	ASD / Main Sense Circuit	The PCM has detected a problem in the ASD relay’s main power-feed circuit, often a short.
P1388	Auto Shutdown Relay Control Circuit	The PCM has detected a fault in the relay’s control (trigger) side of the circuit.[21]
P1389	No ASD Relay Output Voltage At PCM	This strongly suggests a failed relay. The PCM energized the relay but detected no voltage on the output side.[21]
P1489	ASD Relay Circuit	A general fault has been detected in the ASD relay circuit.[21]
P1490	Cooling Fan Relay/ASD Circuit Open Or Short	On some models, these circuits are linked. A fault here indicates an open or short affecting both systems.[21]

How to Test Your Ram’s ASD Relay (DIY Guide)

Testing is a critical step. Do not replace parts you have not tested. The testing procedure depends entirely on which generation of Ram you own.

Part 1: For Plug-In Relays (Gen 2, 3, & 5)

If you have a serviceable, plug-in relay, you have three easy test methods.

Method 1: The “Relay Swap” (The 2-Minute Test)

This is the fastest and easiest test.

Locate your ASD relay using Section 3 of this guide.
Look in the same fuse box for an identical relay with the same part number. Non-critical systems like the Horn, Fog Lights, or A/C Clutch relay are perfect donors.
Pull the ASD relay out and swap it with the identical horn relay.
Result 1: If the truck starts and runs, the ASD relay was bad.
Result 2: If the problem remains, the relay is likely good. (Confirm by testing if the horn still works with the “bad” relay).

Method 2: Multimeter Bench Test

This test is performed on the relay itself after it has been removed. A standard 4-pin relay has pins numbered 85, 86, 30, and 87.

Test A: Test the Internal Coil (Pins 85 & 86)
1. Set your multimeter to Ohms ($\Omega$).
2. Touch the multimeter leads to pins 85 and 86.
3. Expected Result: A reading between 50 and 200 ohms. If you see “OL” (Open Loop/no continuity) or 0.0 ohms (a direct short), the relay’s internal coil is bad.
Test B: Test the “Click” (Pins 85 & 86)
1. Use a 9-volt or 12-volt battery.
2. Connect the battery’s positive to pin 86 and negative to pin 85.
3. Expected Result: You should hear a distinct “click” as the internal electromagnet pulls the switch closed. No click means the relay is mechanically frozen or electrically-dead.

Method 3: Multimeter “Live” Socket Test (Advanced)

This tests the circuit in the fuse box, not just the relay. It is the definitive diagnostic test. (Relay should be removed).

Test A: Key OFF

Socket Pin #	Standard Name	What to Test	Expected Result	What a Bad Result Means
30	Power In	Volts (DC)	Constant 12V+	No power. Check the main fusible link or battery connection.
87	Power Out	Volts (DC)	0V	If 12V+ is present, something is shorted to power.
86	Control In	Volts (DC)	0V	N/A
85	Control Out	Volts (DC)	0V	N/A

Test B: Key ON / Cranking

Test Pin 86 (Control In): Turn the key to “ON”. With the red multimeter lead on pin 86 and the black on a chassis ground, you should see 12V+. This is the power from the ignition.
Test Pin 85 (Control Out): Turn the key to “ON” or “START”. With the red lead on pin 85 and black on ground, you should see the voltage drop to near 0V (less than 1V). This indicates the PCM is providing the necessary ground to activate the relay.
Test Pin 87 (Power Out): If pins 85 and 86 test good, re-insert the relay. Turn the key to “START” and crank the engine. Check for voltage at the Z1 (pin 87) wire. You should see 12V+. If you have 12V on 30, 12V on 86, and ground on 85, but no 12V on 87, the relay is bad.

For a general guide on relay testing, this is a helpful resource:(https://www.youtube.com/watch?v=s9VlmiDTv2o).

Part 2: Testing the 4th Gen (TIPM)

As established, you cannot test a “relay” here. You must test for the results of the ASD/fuel pump relay logic.

Listen for the Fuel Pump: Have a helper turn the key to “ON” (do not crank). Stand near the fuel tank and listen. You should hear a 2-second “whirr” or “hum” as the fuel pump primes. If you hear nothing, the fuel pump relay circuit is the prime suspect.
Check for Spark: Use an inline spark tester. If you have no spark and no fuel pump prime, the problem is almost certainly the ASD/fuel pump relay logic in the TIPM.
The “Bypass” Diagnostic: The most definitive test is to use a TIPM bypass cable or external relay kit.¹⁴ These kits are designed to plug into the fuse box and force power to the fuel pump, bypassing the faulty internal relay. If you install one and the truck starts, you have 100% confirmed a failed TIPM.

ASD Relay Replacement: Procedure and Cost

The cost and procedure to fix a bad ASD relay are wildly different. It can be a 5-minute, $20 fix or a $1,500+ dealership repair.

Part 1: Gen 2, 3, & 5 (Plug-In Relay) Replacement & Cost

This is a simple DIY job.

Procedure:

Disconnect the negative terminal from the truck’s battery.
Locate the PDC/IPM (fuse box) under the hood.
Open the cover and identify the ASD relay using the diagram on the cover’s underside or Section 3 of this guide.
Firmly grasp the old relay and pull it straight up and out of its socket. It may be stiff.
Align the pins of the new relay with the socket and press it firmly into place.
Reconnect the negative battery terminal and test the vehicle.

Cost Analysis:

Cost Type	DIY Cost	Professional Cost	Notes
Part Cost	$15 – $35	$25 – $40	Sourced from
Labor Cost	$0	$70 – $95	Sourced from (Approx 0.5-1.0 hr)
Total	$15 – $35	$95 – $135

Part 2: 4th Gen (TIPM) “Replacement” & Cost

This is not a simple replacement. You are fixing a faulty circuit board, and you have three main options.

Option 1: Full TIPM Replacement (Dealer)
- Procedure: The dealership or a shop replaces the entire TIPM unit and programs the new one to your truck’s VIN.
- Cost: $1,500 or more.
- Downside: This is extremely expensive, and a new Mopar TIPM may still contain the same faulty relay design.
Option 2: TIPM Rebuilding Service
- Procedure: You remove your TIPM from the truck and mail it to a specialist company. They de-solder the faulty internal relay, solder in a new, more robust relay, and mail the unit back to you.
- Cost: $200 – $500.
- Downside: Your truck will be non-operational for several days during shipping.
- Resource: Companies like(https://tipmrebuilders.com/) specialize in this service.
Option 3: External Relay / Bypass Kit (DIY)
- Procedure: This is the most common DIY fix. You purchase a kit that plugs into your TIPM and creates a new, external, and serviceable relay circuit for the fuel pump, completely bypassing the failed internal one.
- Cost: $40 – $100.
- Downside: It’s a non-OEM fix, but it is effective, permanent, and vastly cheaper.

ASD Relay vs. Fuel Pump Relay: What’s the Difference?

This is a common point of confusion, especially on 4th Gen models.

Think of it as a hierarchy of power:

The ASD Relay is the “master” relay. When it’s on, it provides power to multiple engine systems at once, including the fuel pump relay’s control circuit.
The Fuel Pump Relay is a downstream relay. It receives its power or “on” signal from the ASD relay circuit and then sends that power only to the fuel pump.

Diagnostic Key: A failure in the ASD relay (or its logic) will kill power to both the fuel injectors and the ignition coils. A failure in only the fuel pump relay will kill power to the fuel pump, but you will still have spark at the spark plugs.

If you have no fuel AND no spark, the problem is upstream at the ASD relay.

If you have no fuel but you DO have spark, the problem is downstream at the fuel pump or its dedicated relay.

Frequently Asked Questions (FAQs)

Q: Where is the ASD relay on a 2011 Dodge Ram 1500?

A: There is no plug-in ASD relay on a 2011 Ram 1500. The ASD function is built into the TIPM (fuse box). The common “crank-no-start” issue is caused by a faulty fuel pump relay that is soldered to the TIPM’s internal circuit board and cannot be serviced.

Q: Can you bypass an ASD relay?

A: You can, but it is not recommended.34 Bypassing the ASD relay defeats the critical safety feature that cuts fuel and spark in a crash.3 It is a diagnostic step, not a fix. However, bypassing the specific fuel pump relay on 4th Gen models with an external-relay kit is a common and accepted long-term repair.

Q: What happens if the ASD relay is bad?

A: Your engine will most likely do one of two things: it will crank but not start (due to no fuel and no spark), or it will start and then stall immediately after the 2-second fuel prime.

Q: Is the starter relay the same as the ASD relay?

A: No. They are two separate relays that perform different jobs, though they are often located in the same fuse box and may look identical. The starter relay’s only job is to send high-amperage power to the starter motor to crank the engine. The ASD relay’s job is to power the fuel injectors, ignition coils, and fuel pump to run the engine.

Dodge Ram 1500 ASD Relay Location, Symptoms & Testing (All Years Guide)