How To Test The Starter Motor (Dodge 3.9L, 5.2L, 5.9L)

Testing the starter motor on your Dodge 3.9L, 5.2L, 5.9L (or 5.2L, 5.9L) is not hard. In this tutorial, I'll show you how to test it on the vehicle in a step-by-step manner.

Important Safety Precautions

SUGGESTION 1: You don't need to remove the starter motor to test it. The photos I'm using show it off of the vehicle just to make it easier to show you where to make your connections. If you do need to bench test it (test if off of the vehicle), the following tutorial will help you: How To Bench Test A Starter Motor (Step By Step) (at: easyautodiagnostics.com).

SUGGESTION 2: All the tests, in this tutorial, need to be done with a fully charged battery in your Dodge vehicle. A discharged battery will cause you to reach the wrong diagnostic conclusion and have you wasting time and money! Also, the battery cable terminals and battery posts must be clean and corrosion free.

SUGGESTION 3: You'll need to raise your Dodge (or ) vehicle up in the air to access the starter motor. So use jack stands and don't trust the jack alone! Take all necessary safety precautions, like using jack stands to hold up the vehicle, wearing eye-protection (safety glasses), etc.

SUGGESTION 4: If your vehicle has a standard transmission, make sure that it's out of gear and in neutral, and the parking brake is activated/on.

Symptoms Of A Bad Starter Motor

When the starter motor goes bad on your Dodge vehicle, it will not crank the engine (this is called a no-crank condition in tech speak). You'll also see one or several of the following symptoms:

1. The engine doesn't turn over (crank) when you turn the key to start the engine.
2. A jump start doesn't help. The vehicle's engine still refuses to crank.
3. The battery has been charged and/or replaced and still your vehicle does not crank.
4. When you turn the key to crank the engine, all you hear is a small knock and nothing else.

Although the above list is a not a very complete list of symptoms, the theme that runs thru' them, and any other related symptom, is that the engine will not turn over when you try to start it.

Now, in case your vehicle does crank but the engine doesn't start, you may want to take a look at the following tutorial: How To Test A No Start Condition (Dodge 3.9L, 5.2L, 5.9L).

Tools Needed To Test The Starter Motor

You don't need expensive test equipment to test the starter motor on your Dodge vehicle but you do need a few things. These are:

1. Jack.
2. Jack stands.
3. Remote starter switch.
   • If you'd like to see what a remote starter switch looks like, you can follow this link: Actron CP7853 Remote Starter Switch For 6V And 12V Automotive Starting Systems (at: amazon.com).
   • You can either buy this tool online or you can buy it at your local auto parts store (AutoZone, O'Reilly Auto Parts, etc.).
4. Multimeter or a 12 Volt automotive test light.
   • If you don't have a multimeter or need to upgrade yours, this is the one I use: Tekpower TP8268 AC/DC Auto/Manual Range Digital Multimeter (at: amazon.com).
5. A wire piercing probe.
   • This tool is not an ‘absolute must-have tool’ but I can tell you from experience that it makes it a whole lot easier to probe the S terminal wire for the Start Signal.
   • If you'd like to see what this tool looks like, you find out more about it here: Wire Piercing Probe Tool Review (Power Probe PWPPPPP01).
6. A helper.

As you can see, you don't need anything expensive. OK, let's turn the page and get started with the first starter motor test.

STARTER TEST 1: Applying 12 Volts To The Starter Motor S Terminal

OK, this is what you signed up for! To get our starter motor diagnostic on the way, the very first thing we'll do is apply 12 Volts to the S terminal of the starter motor (see the photos in the image viewer).

You can disconnect the wire that attaches to the S terminal or you can leave it connected to it (to apply 12 Volts to the S terminal), whatever is easiest for you.

TIP: Getting to the starter motor solenoid S terminal (to manually apply 12 Volts) can be a challenge. What I do is use a wire piercing probe to pierce the S terminal wire (while it's still connected to the S terminal) and then I connect my remote starter switch to it and proceed from there, I suggest you do the same (to see what this tool looks like, go here: Wire Piercing Probe Tool Review (Power Probe PWPPPPP01)).

NOTE: Don't have a multimeter or need to upgrade your? This is the one I use and recommend: Tekpower TP8268 AC/DC Auto/Manual Range Digital Multimeter (at: amazon.com).

OK, this is what you'll need to do:

1. 1

   Jack up your Dodge vehicle and place on it jack stands. Remember, to only way to gain access to the starter motor is from underneath the engine.

2. 2

   Disconnect the battery negative (-) terminal.
   
   You'll reconnect it back in one of the following steps, for now, it's a safety precaution as you set up the test.

1. 3

   Attach one of the remote starter switch's terminals to the S terminal of the starter motor solenoid.
   
   This is easier said than done, so take your time and make sure the connection is on the S terminal of the starter motor solenoid.
   
   Also, in case you're wondering, you can leave the starter motor solenoid's S terminal wire connected to the engine's wiring harness connector or not, the test will work either way.

2. 4

   Reconnect the battery negative (-) cable to the battery negative (-) post.
   
   Connect the remaining remote starter switch ‘alligator’ type connector to the battery positive (+) terminal.
   
   Now, apply 12 Volts to the S terminal wire of the starter motor starter solenoid with your remote starter switch. As you apply these 12 Volts (to the S terminal wire of the starter motor solenoid), you'll get one of two results:

   1. The starter will activate and will turn over the engine
   2. -OR-
   3. The starter motor won't do a thing.

Let's take a look at what your test results mean:

CASE 1: The starter motor came to life and cranked the engine. This test result lets you know that the starter motor is OK and functioning. It also tells you that the probable cause, of it not working when you turn the key to start the engine, is a lack of the 12 Volt Start signal on the S terminal of the starter motor solenoid.

The next step is to go to TEST 2 and see if the starter motor is getting the 12 Volt Start signal on the S terminal wire (circuit). Go to: TEST 2: Verifying The Start Signal.

CASE 2: The starter motor DID NOT crank the engine. This usually means that your starter motor is bad and needs to be rebuilt or replaced.

I suggest 2 more tests and these are make sure that the starter motor is getting its 12 Volt Start signal and to test the battery cable (that attaches to the starter motor solenoid) for corrosion. This can be accomplished very easily with a voltage drop test.

• Go to: TEST 2: Verifying The Start Signal.
• Go to: TEST 3: Voltage Drop Testing The Battery Cable.