When the stater motor fails, it'll usually just not crank the engine. You'll turn the key to crank and start the engine, but nothing happens.
The cool thing is that testing the starter motor isn't that hard. This tutorial will help you test the starter motor on the 1996, 1997, 1998, and 1999 Chevrolet and GMC equipped pick-ups with a 5.0L and 5.7L V8 engine.
All the test steps are explained in a step-by-step way.
You'll be able to find out if the starter motor is defective or not.
Contents of this tutorial:
- Important Safety Tips And Precautions.
- Tools Needed To Test The Starter Motor.
- 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.
- Where To Buy The Starter Motor And Save.
- More GM 4.3L, 5.0L, and 5.7L Tutorials.
Important Safety Tips And Precautions
TIP 1: Don't remove the starter motor to test it, since the starter motor test (in this tutorial) is an on-car test.
If you have removed it, you can bench-test it and the following tutorial will help you: Bench Testing The Starter Motor.
TIP 2: It's very important that the battery be fully charged before doing the tests.
Also, the battery posts and battery terminal cables should be clean and corrosion free.
TIP 3: If your vehicle has a standard transmission, make sure that it's out of gear and in neutral, and that the parking brake is activated/on.
Tools Needed To Test The Starter Motor
Here's a list of the tools I recommend you use to follow the test steps in this tutorial:
- 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 these tools are anything but expensive and more importantly, they'll help you test it without complications.
TEST 1: Applying 12 Volts To The Starter Motor S Terminal
The first order of business is to apply 12 Volts to the starter solenoid's S terminal with a remote start switch.
The remote start switch will act as our ignition key and is the safest way to manually apply battery power to the starter motor solenoid's S terminal.
If the starter motor is functioning correctly, then manually applying 12 Volts (from your pick-up's battery) to it should get it to engage and crank the engine.
If the starter motor is defective, then juicing it up manually with 12 Volts will have no effect on it.
IMPORTANT: Before you perform this test remove the key from the ignition switch to prevent the engine from accidentally starting.
IMPORTANT: Use jack stands when raising your vehicle to access the starter motor. Don't trust the jack to keep your pick up or SUV up in the air!
OK, these are the test steps:
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.
Reconnect the negative battery cable to the battery negative post.
NOTE: 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 Chevy/GMC pickup or SUV has a standard transmission, make sure it's out of gear before you make this last connection.
Activate the starter motor with your remote starter switch. As you apply these 12 Volts (to the S terminal of the starter motor), you'll get one of two results:
1) The starter will activate and will turn over the engine -OR- 2) The starter motor won't do a thing.
Let's examine your test result:
CASE 1: The starter motor cranked the engine. This is the correct test result and tells you that the starter motor itself is OK.
Since the starter motor is not engaging when you use the ignition key, the next step is to go to: TEST 2: Verifying The Start Signal.
CASE 2: The starter motor DID NOT crank the engine. This usually means that the 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 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 tests 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 that the starter motor is bad and needs to be replaced.