TEST 1: Applying 12 Volts To The Starter Motor S Terminal
The first thing that we need to do, to find out if your Honda Civic's starter motor is fried (or not) is to manually apply 12 volts from your Civic's car battery to the starter motor solenoid's S terminal.
The purpose of this test is to bypass the ignition switch and everything in between it and the starter motor and directly test the starter motor to see if it cranks (or not) the engine.
You can use a home made jumper wire or a power probe to apply battery power to the starter motor (I use a power probe myself and if you need to see what this tool looks like, take a look at this article I wrote on it: -at: easyautodiagnostics.com).
There's one more tool I use and it's a wire piercing probe to pierce the S terminal wire and then I connect my remote starter switch to it and proceed from there. (to see what this tool looks like, go here: Wire Piercing Probe Tool Review (Power Probe PWPPPPP01)).
IMPORTANT: Before you perform this test, remove the key from the ignition switch to prevent the engine from accidentally starting.
OK, this is what you'll 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 alligator-type terminals of the remote starter switch to the S terminal of the starter motor solenoid.
Here's how I do it: I leave the S terminal wire connected to the starter motor. I then use a wire piercing probe to pierce the S terminal wire. I then connect the remote start switch to the wire piercing probe.
Reconnect the negative battery cable to the battery negative post. Make sure that the battery cables and posts are clean.
Connect the remaining alligator-type terminal of the remote starter switch to the battery positive post.
IMPORTANT: If your Honda Civic has a standard transmission, make sure it's out of gear before you make this last connection.
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: The starter will activate and will turn over the engine or 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 test result let's you know that your Honda Civic's starter motor is OK and functioning. This also tells you that the starter motor is NOT receiving the activation signal from the ignition switch.
The next step is to go to TEST 2 and see if the starter motor is getting the 12 Volt signal 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 Honda Civic's 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 signal signal and to test the battery cable (that attaches to the starter motor starter motor) for corrosion. This can be accomplished very easily with a voltage drop test.
If the above two test confirm that the start signal IS present and there's no voltage drop on the battery cable feeding battery power to the starter motor... then you can confidently conclude your Honda Civic's starter motor is bad and needs to be replaced.
TEST 2: Verifying The Start Signal
If you've reached this point, you have confirmed two very important things:
One: That when you turn the key to crank your Honda Civic's engine... the starter motor does not activate.
Two: You've done TEST 1 and have confirmed that the starter motor DOES run when you manually applied battery power from your Honda Civic's battery.
To see why the starter motor doesn't activate when you turn the key to crank the engine... we need to see if the starter motor solenoid is getting the start (crank) signal.
So in this test step, you're gonna' use a multimeter to see if the start signal is present when you turn the key to crank your 1.7L Honda Civic's engine.
You can use a multimeter or a 12 Volt automotive test light.
Ok, here's what you'll need to do:
Connect the RED multimeter test lead to the S terminal wire of the starter motor.
The S terminal wire, of the starter solenoid, must remain connected to it's engine wiring harness connector for this test to work.
Attach 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 ground the black multimeter test lead directly to the battery negative terminal since you may NOT be able to find a clean and rust-free spot to ground the multimeter's black test lead.
Now, have your helper hop inside the vehicle and turn the key to crank your Civic's 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: Either 10 - 12 Volts DC or no voltage at all.
OK, let's examine your test result:
CASE 1: The multimeter registered 10 to 12 Volts. This test result let's you know the starter solenoid is receiving the start 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: TEST 3: Voltage Drop Testing The Battery (+) Cable.
CASE 2: If 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 crank signal, your Honda Civic's 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.