If your 3.8L V6 Ford Mustang is suffering a ‘does not crank condition’, then there's a good chance that the starter motor is defective. Thankfully, testing the starter motor isn't that hard.
In this tutorial I'll explain how to do it in a step-by-step way. You'll be able to find out if it's defective and behind the ‘no crank’ problem or not.
Contents of this tutorial:
- Important Safety Tips And Precautions.
- Symptoms Of A Bad Starter Motor.
- Tools Needed To Test The Starter Motor.
- Starter Motor Solenoid S Terminal Info.
- TEST 1: Applying 12 Volts To The Starter Motor S Terminal.
- TEST 2: Verifying The Start Signal.
- TEST 3: Voltage Drop Testing The Battery (+) Cable.
- More 3.8L Ford Mustang Tutorials.
You can find this tutorial in Spanish here: Cómo Probar El Motor De Arranque (1995-1998 3.8L Ford Mustang) (at: autotecnico-online.com).
NOTE: You can find the wiring diagrams for the 1995 3.8L Ford Mustang starter motor circuit here: Starter Motor Wiring Diagram (1995 3.8L V6 Ford Mustang).
You can find the wiring diagrams for the 1996-1998 3.8L Ford Mustang starter motor circuit here: Starter Motor Wiring Diagram (1996-1998 3.8L V6 Ford Mustang).
Important Safety Tips And Precautions
TIP 1: The starter motor test described in this tutorial ears and on car test. You don't have to remove the starter motor from your Ford Mustang to tested.
If you have removed it, no problem. The following tutorial will help you to bench test it: Bench Testing The Starter Motor.
TIP 2: It's important that the battery, in your 3.8L Ford Mustang be fully charged. Testing the starter motor with a less than fully charged battery will give you a untrustworthy test result (that could make you end up buying parts your Mustang doesn't need).
You also need to make sure that the battery cable terminals and battery post are clean and free of corrosion.
TIP 3: If your Ford Mustang has a standard transmission, make sure that it's out of gear and in neutral, and that the parking brake is activated/on.
TIP 3: You'll need to raise your Ford Mustang to access the starter motor. Use jack stands to keep it up. Don't trust the jack!
Symptoms Of A Bad Starter Motor
The most common symptom, that you'll see when the starter motor is bad, is the engine does not turn over when you turn the key to crank and start your Ford Mustang's 3.8L V6 engine.
The starter motor can also fail intermittently, which means that it will start the car most or some of the time and then it won't.
Here's a basic list of symptoms you see when the starter motor has failed completely:
- Jump starting the engine doesn't make it crank over.
- The battery has been charged and/or replaced and still your Ford Mustang does not crank.
- When you turn the key to crank the engine, all you hear is a small knock and nothing else.
Tools Needed To Test The Starter Motor
Testing the starter motor does require some basic tools. The cool thing is that they aren't expensive. Here's a basic list of what you'll need:
- Remote starter switch.
- If you'd like to see what a remote starter switch looks like, you can follow this link: Sunpro Actron CP7853 Remote Starter Switch.
- You can either buy this tool online or you can buy it at your local auto parts store (AutoZone, O'Reilly, Pepboys, etc.).
- 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.
- 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).
- A helper.
As you can see, you don't need anything expensive. OK, let's turn the page and get starter with the first starter motor test.
Starter Motor Solenoid S Terminal Info
There are 2 types of starter motors that are used on the 3.8L V6 Ford Mustang. The main difference lies in how the S terminal wire is attached to the starter solenoid.
TYPE 1: The factory original starter motor has the S terminal wire connecting to a male spade terminal on the starter solenoid.
On this type, the S terminal wire has a female quick disconnect type connector.
TYPE 2: On the after-market starter motors, the S terminal wire connects to a threaded stud and a nut fastens it in place.
On this type, the S terminal wire has a circular (ring) connector. To remove this connector, you have to remove the nut that locks/fastens it in place.
Both type of starter motors work in the exact same way and are pretty much tested in the same way too.