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).
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 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.
You can do this one of two ways:
1.) Leave the 'S' wire connected to the 'S' terminal and use a wire piercing probe (on the 'S' wire). Then, connect one end of the remote start switch to the wire piercing probe. This is the method I use.
2.) Disconnect the 'S' wire from the 'S' terminal. Connect one end of the remote start switch to the male spade terminal of the 'S' terminal.
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 test result lets 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 solenoid) 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:
Set your multimeter to Volts DC mode.
Ground the black multimeter test lead directly on the negative (-) battery terminal using a jump start cable.
You can also Ground it on the engine, if you can find a clean, unpainted and rust-free spot of metal.
Disconnect the 'S' wire from the starter motor's 'S' terminal.
Connect the red multimeter test lead to the female terminal of the 'S' wire using an appropriate tool.
Have your helper turn the key to crank the engine when the test is setup.
Your multimeter should read 10 to 12 Volts DC.
OK, let's examine your test result:
CASE 1: The multimeter registered 10 to 12 Volts. This test result lets 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.