How to Troubleshoot the Starter in Vehiclesby Contributing Writer; Updated June 12, 2017
There are several things that can go wrong with the starter motor in your Vehicles Internal components may wear out; someone may have mounted the starter improperly, eventually causing it to fail; or mounting bolts may become loose. Bad connections to the starter or another component in the starter circuit may become faulty, as well. There are a few tests and checks you can perform Vehicles home to help troubleshoot your Vehicles starter motor. Before you proceed with these tests though, make sure you have a fully charged battery in good condition.
Under The Hood:
- How to Troubleshoot the Starter in a 1996 Ford F150
- How to Troubleshoot a Starter for a Ford F-150
- How to Troubleshoot the Starter in a Chevrolet Silverado
Park your Ford F-150 on level ground, release the parking brake and raise the front of the truck with a floor jack.
Secure your truck on jack stands and block the rear wheels with a couple of chocks. Then apply the parking brakes.
Disable the ignitions system by unplugging the electrical connector at the coil pack to prevent your F-150 from starting during these tests. To find the coil pack, just follow the wires from the spark plugs to the other end where they attach to the coil pack.
Crank the engine and make sure it will not start before you begin troubleshooting.
Troubleshooting the Starter
Set your voltmeter to the 20 volts range and connect the meter probes to the battery positive terminal and to the "B+" terminal at the back of the solenoid, which is the cylinder mounted on top of the starter. Crawl under your truck to reach the starter solenoid. The "B+" should be marked as such. If not, just follow the red battery cable to the starter, which connects to this terminal.
Turn on your voltmeter to measure voltage drop and ask an assistant to crank the engine for 6 seconds. Read your meter display. It should read 0.5 volts or less. If the meter detects a voltage drop of more than 0.5 volts, check the connections for dirt, corrosion and looseness between the starter "B+" terminal and the positive battery terminal. If the connections are clean and tight, you need to replace the battery cable.
Connect your meter probes between the positive battery terminal and the "M" circuit terminal at the back of the starter solenoid. This is the bottom stud with a small metal strip that connects to the starter case.
Set your voltmeter to the 20 volts range and ask your assistant to crank the engine for 6 seconds. Read your meter display. It should read 0.5 volts or less. If the meter detects a voltage drop of more than 0.5 volts, there is high resistance within the starter. Take your starter to a repair shop for inspection or replace it. Turn off the voltmeter.
Connect the coil pack electrical connector and try to start the engine. If the starter passed the first two previous tests and fails to engage, the starter or solenoid might be faulty. Also, you might have a faulty ignition switch, Park/Neutral position switch (if equipped with automatic transmission) or clutch pedal position switch (if equipped with a manual transmission). Also, make sure the starter is properly mounted, if it is not disengaging. Otherwise, you might have a faulty starter, solenoid or ignition switch.
Remove the starter motor and take it to a repair shop for inspection, if the starter engages but fails to turn the engine. There is a possibility the starter is in good condition, but your F-150 engine is seized, says James E. Duffy in "Modern Automotive Technology."
Check the mounting bolts at the starter motor and make sure they are tight and the unit is properly mounted. The starter may become noisy if the bolts are loose. Also, a bad armature, field pole shoes or some other internal component may cause the starter to make noise. Take the starter to a repair shop for inspection.
Items you will need
Jack stands (2)
Check the contacts on the battery terminal for corrosion. Clean any corrosion off of the battery contacts with a brush and a mixture of water and baking soda. Use gloves when doing this because battery acid can hurt your skin.
Place a voltmeter, or a battery charger with a charge indicator, on the battery. If the battery reads 12 volts or more, proceed to Step 3. If not, charge the battery until it reads 12 volts. If the F-150 still does not start, move on to the next step.
Disconnect the starter wire from the back of the starter. If your car is fuel injected, remove the larger of the two wires connected to the starter. Place a voltmeter onto the wire and have a second person turn the ignition key. If the voltmeter reads 12 volts, the ignition switch is sending power to your starter.
Locate the two large connector posts on the back of the solenoid. Place a screwdriver across both posts to create a direct connection between the battery and starter. This eliminates the need for the starter solenoid. The starter should turn on but not crank the engine. If the starter does not turn on, the starter is defective. If the starter does turn on, the starter is not the issue. Make sure the F-150 is in neutral and the parking break is set when you do this step.
Items you will need
Battery charger (optional)
Prior to Testing
Inspect the condition of the battery cables and their clamps. Make sure they are tight where they connect to the battery terminals.
Test the battery's condition, connecting a voltmeter to the battery--red probe to the positive terminal and black probe to the negative one. Make sure the voltage is greater than 12.5 volts.
Check the starter solenoid's wiring connections; use the wiring path described in the Tips.
Connect the starter solenoid switch terminal to a voltmeter or a test light. On models made in 1999 or later, this is the one with the small purple wire.
Have an assistant turn the truck's ignition switch to the "On" or "Start" position while you observe the light or voltmeter. Check for the test light to shine brightly or voltage to appear on the voltmeter.
Check the starting-system circuit if voltage does not appear, taking into account the wiring pattern described below.
Crank the engine and observe the battery voltage if the starter turns over slowly; the voltage shouldn't drop below less than 8.5 volts. Connect an inductive-type ammeter to the battery and observe the starter's draw on the battery; it shouldn't exceed 400 amps (350 for models made before 2007).
Remove the starter and mount it in a bench vise for a bench test if voltage appears on the meter/light but the starter motor will not operate.
Connect the starter's B+ terminal to the positive terminal of a test battery using a jumper cable. Connect another jumper cable to the battery's negative terminal and the starter body. Connect a spare starter switch to the positive battery terminal and the solenoid's S terminal.
Apply battery voltage to the S terminal using the starter switch and see if the solenoid plunger extends with the shift lever and overrunning clutch and then rotates the pinion drive
Replace the starter motor if the pinion drive extends but doesn't rotate--the starter is defective but the solenoid works. If the solenoid clicks but there isn't any movement, the problem could be the motor, the solenoid or both.
Items you will need
12-volt test light (optional)