STARTER TEST 1: Applying 12 Volts To The Starter Motor S Terminal
To see if the starter motor is bad on your 3.0L Honda Accord (Odyssey or Acura CL), we'll start by manually applying 12 Volts to the S terminal of the starter motor solenoid.
In the photo above, the S terminal of the starter motor solenoid is labeled with the letter S.
The fastest, easiest, and safest way to do this is with a tool called a remote start switch, although you can use a home made jumper wire if you want.
Applying 12 Volts to the S terminal of the starter motor's solenoid will help us eliminate or blame the starter motor as bad right off the bat. How? Because when we apply the 12 Volts, the starter motor will either activate and crank the engine or do nothing at all.
OK, to get this pot of water boiling, this is what you need to do:
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 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.
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) 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 is the correct test result and lets you know that the starter motor is OK and functioning. This test result also tells you that the starter motor is not working due to a lack of the 12 Volt Start signal that comes from the ignition switch.
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) for corrosion. This can be accomplished very easily with a voltage drop test.
STARTER TEST 2: Verifying The Start Signal
In this test, we're gonna' see if the starter motor is getting an activation signal when you turn the key to crank the engine. This is a pretty simple test that you'll accomplish with a multimeter or a 12 Volt automotive test light (although I prefer the multimeter).
This activation signal is a 12 Volt signal that arrives at the starter motor thru' the S terminal wire of the starter motor solenoid.
NOTE: You can accomplish this test with the wire (that connects to the S terminal) connected or disconnected to the S terminal of the starter motor solenoid.
Here's what you'll need to do:
Connect the red multimeter test lead to the wire that connects to the starter motor solenoid's S terminal.
You can use a wire piercing probe to connect the multimeter's red test lead to the S terminal wire or you can disconnect the wire and manually hold the multimeter's red test lead to the wire's metal terminal.
Connect the black multimeter test lead to a clean and rust-free spot on the engine or on the vehicle frame.
Here I'm going to recommend something to you: Use a battery jump start cable to connect the black multimeter test lead to a clean Ground point on the engine. The reason why is that depending on how rusty and dirty the underneath of the vehicle, you may NOT be able to find a clean and rust-free spot to connect the multimeter's black test lead.
Now, have your helper crank the engine.
The engine won't turn over, but the idea is to verify that the starter motor solenoid is getting the 12 Volt start signal from the ignition switch.
Your multimeter is going to register one of two results: A voltage between 10 to 12 Volts DC or no voltage at all.
OK, let's make sense of the readings that your multimeter recorded in the test:
CASE 1: Your multimeter registered a voltage between 10 to 12 Volts. This is the correct test result and it let's you know the starter solenoid is receiving the Start signal (crank signal).
This means that we can forget about the safety-neutral switch and the ignition switch being bad. OK, now the next test is to do a very easy and simple voltage drop test. Go to: STARTER TEST TEST 3: Voltage Drop Testing The Battery (+) Cable.
CASE 2: Your multimeter DID NOT register 10 to 12 Volts. This result exonerates the starter motor. Your starter motor is not bad.
Here's the reason why: Without this 10 to 12 Volt Start signal, the starter motor will not crank the engine. Now, although it's beyond the scope of this article to test the neutral-safety switch or the ignition switch, you have eliminated the starter motor and this means saving money by not buying a part your vehicle does not need.