You can easily and quickly test the starter motor with a few basic hand tools and a multimeter. In this tutorial, I'll show you how in a step-by-step manner.
You'll easily determine if the starter motor is good or bad with your test results.
NOTE: This is an on-car test of the starter motor. You'll notice that the photos I'm using have the starter motor off of the vehicle. This is only to show the test connections.
Contents of this tutorial:
APPLIES TO: This tutorial applies to the following vehicles:
- 3.1L V6 Buick Century: 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005.
- 3.1L V6 Buick Regal: 1990, 1991, 1992, 1993, 1994, 1995, 1996.
- 3.1L V6 Buick Skylark: 1994, 1995, 1996, 1997, 1998.
- 3.1L V6 Oldsmobile Achieva: 1994, 1995, 1996, 1997, 1998.
- 3.1L V6 Oldsmobile Cutlass: 1997, 1998, 1999.
- 3.1L V6 Oldsmobile Cutlass Ciera: 1994, 1995, 1996.
- 3.1L V6 Oldsmobile Cutlass Supreme: 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997.
Important Testing Tips
The following testing tips will help you test the starter motor without complications:
TIP 1: All starter motor tests must be done with a fully charged battery.
TIP 2: The battery cable terminals and the battery posts should be clean and corrosion-free before starting the tests.
TIP 3: Read the entire tutorial first to familiarize yourself with the tests.
TIP 4: Use jack stands for safety. Don't trust the jack alone to keep your vehicle up in the air while you're underneath it!
TIP 5: Use safety glasses while working underneath the vehicle. Take all necessary safety precautions. Be alert and think safety all of the time.
Symptoms Of A Bad Starter Motor
It's been my experience over the years that a starter motor failure will usually cause one of two problems:
- An engine no-crank problem. Specifically, you turn the key to crank and start the engine, but nothing happens.
- An intermittent engine no-crank problem. In this type of scenario, the starter motor works fine most of the time, but it doesn't now and then.
If you're currently experiencing an intermittent engine no-crank problem, you must test the starter motor when it isn't cranking the engine. Otherwise, your test results will always indicate that the starter motor functions correctly.
Tools Needed To Test The Starter Motor
The tools you'll need to test the starter motor are inexpensive. Here's a list of what you'll need to follow the instructions in this tutorial:
- You'll need to raise your vehicle to gain access to the starter motor.
- Jack stands.
- A 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
- You can either buy this tool online or you can buy it at your local auto parts store (AutoZone, O'Reilly Auto Parts, Pepboys, etc.).
- A multimeter or a 12 Volt automotive test light.
- If you don't have a multimeter or need to upgrade yours, check out my recommendation here: Buying A Digital Multimeter For Automotive Diagnostic Testing (at: easyautodiagnostics.com).
- 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 can find out more about it here: Wire Piercing Probe Tool Review (Power Probe PWPPPPP01).
- A helper.
TEST 1: Applying 12 Volts To The 'S' Terminal
To get your starter motor diagnostic underway, the first thing I'm going to ask you to do is to apply 12 Volts DC directly to the starter motor solenoid's 'S' terminal.
If the starter motor is functioning, it'll immediately crank the engine (as you're applying 12 Volts to its 'S' terminal).
If the starter motor doesn't crank the engine, this generally tells you that the starter motor is bad.
IMPORTANT: Remove the key from the ignition switch for this test.
OK, let's begin:
Raise your vehicle and place on it jack stands to gain access to the starter motor.
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.
Attach one end of the remote starter switch to the battery positive (+) post.
Attach the other end of the remote starter switch 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.
Reconnect the battery negative (-) cable to the battery negative post.
Apply 12 Volts to the 'S' terminal wire of the starter motor starter solenoid with your remote starter switch.
You'll get one of two results:
1.) The starter will activate and will turn over the engine.
2.) The starter motor won't do a thing.
Let's take a look at what your test results mean:
CASE 1: The starter motor cranked the engine. This is the correct and expected test result.
With this test result you can conclude that the starter motor itself is OK. The next step is to see if the starter motor is getting the 12 Volt Start signal on the 'S' terminal wire. Go to: TEST 2: Verifying The 12 Volt 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 you perform two more tests. First, make sure the starter motor is getting its 12 Volt Start signal. Second, voltage drop test the battery cable (that attaches to the starter motor solenoid).