Tip & How-To about Cars & Trucks

How to Troubleshoot a Starter Solenoid

Without it, your car cannot go anywhere. Yet, a starter solenoid's only job is to complete the circuit between the battery and the starter when you turn the key to start. However, not every start goes as smoothly as it should, and the solenoid might refuse to crank the engine, disengage the pinion gear or might keep the starter motor running. Fortunately, even with very little knowledge of electricity you can learn to troubleshoot a problematic solenoid. Gain the skills to test both on-starter and remote-mounted solenoids. For these tests, it is better if you have the help of an assistant.
Things You'll Need
Two jumper wires, 1 to 2-foot-long
Multimeter
Step 1
Check that your car battery is fully charged before beginning these tests.
Step 2
Move the gear to neutral if you are diagnosing a car with a standard transmission or park if you are diagnosing a car with an automatic transmission.
Step 3
Apply the parking brake and make sure to stay away from moving engine parts as you proceed with these tests.
Step 4
Disconnect the coil high tension cable from the distributor cap and ground it using a short jumper wire.
Step 5
Ask your assistant to turn the ignition key to start while you listen for a click at the starter solenoid. If you hear a firm click, go to step 9 if you have an on-starter solenoid; go to steps 10 and 11 if you have a remote-mounted solenoid. If you hear a weak click or repeated click sounds, go to the next step.
Step 6
Unplug the small control circuit wire at the solenoid terminal. If there are two small wires, disconnect the one marked with an "S"; otherwise, check the wiring diagram for your particular vehicle to locate this wire.
Step 7
Connect a jumper wire to the battery positive terminal. As you bring the other jumper wire’s end in touch with the solenoid’s control circuit terminal you should hear a solid click; if you do not hear any sounds or hear a weak or chattering sound, make sure the solenoid is properly grounded and there is no corrosion or other substance preventing a good ground. Repeat the test. If you still don’t hear a solid click, replace the solenoid.
Step 8
Unplug the small control circuit wire at the solenoid terminal. Ask your assistant to turn the key to start. Using a voltmeter, test for voltage at the control circuit wire. If the meter reads 0 volts, there is an open in that part of the circuit preventing the solenoid from operating the starter. Locate and fix the open.
Step 9
Ask your assistant to turn the key to start. Check for a voltage drop between the solenoid's battery terminal and the starter motor strap. The voltage drop should be no more than 0.2 volts; otherwise, replace the solenoid. Make sure the battery cable is well connected to the solenoid. Remember, this step is only for an on-starter solenoid.
Step 10
Ask your assistant to turn the key to start. Check for a voltage drop across the two cable connections on the solenoid. The voltage drop should not exceed 0.2 volts. If it does, make sure the cable connections are completely clean and well connected. If you still read over 0.2 volts, replace the solenoid. Remember, this step and the next one are only for remote-mounted solenoids.
Step 11
Unplug the small control circuit wire at the solenoid’s terminal. Using your multimeter, measure the resistance between the control circuit terminal and the solenoid’s ground bracket. If the resistance is above 5 ohms, replace the solenoid. Remember, this step is only for remote-mounted solenoids.

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1 Answer

What would make the starter engage when the key out of the ignition


Your problem seems to be a faulty solenoid. The solenoid is a little monster that lives on top of the starter motor, and its job is twofold. Firstly, it supplies full battery power to the starter motor, and secondly it drives a gear on the starter to engage with the engine flywheel.
Now, your problem. The first guess could be the ignition switch, but fitting a toggle seems like a fairy tale answer. Check the starter solenoid to see if there is a frayed wire on the thin wire that connects to the starter, or possibly a frayed wire on the battery cable that is shorting to the small connector. Otherwise, I have seen the terminal of this small wire actually become loose and turn in the direction of the battery cable, which is also connected to the solenoid. A short here will cause the problem you are describing.
Finally, the solenoid could have a short circuit inside the body, which means replace the solenoid.

Dec 21, 2014 | 1994 Nissan Pickup

2 Answers

won't start


How about corroded battery cables (internal)

Fusible Link wiring corroded & open circuit,does
everything electrical work except the starting circuit?

Turn key & have power to starter solenoid ?
Neutral Switch !
Ignition Switch !

Tough to guess without wiring diagrams,
to see where to start testing

Can't fix what you don't know you have

Oct 02, 2012 | 1990 Ford F150

2 Answers

Solenoid under cab getting red hot


I am sorry but you have this posted in the wrong product category. Please re-post the problem.

Jun 17, 2012 | Cars & Trucks

1 Answer

I have a 2000 Grand Caravan that will ONLY start with a JUMP ........ the starter clicks and WILL start the VAN the battery is GOOD and new it was checked 2 times by 2 different places ..... the Alternator works find that was checked as well .............. if I jump the VAN it starts right away and runs forever till I turn it off ...... it will ONLY turn over with a JUMP what do I do !!!


it sounds like you may have a bad starter solenoid and the extra voltage from the jumper vehicle is enough to complete the circuit through the solenoid to allow the starter to turn over.sometimes the solenoid contacts get very dirty and can`t complete the circuit on its own without a jump.i think these have a bosch starter system on them and you can replace the contacts only in the solenoid.

Apr 08, 2011 | 2000 Dodge Grand Caravan

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