I've worked in a variety of hands-on professions and love to write about topics that can save readers from needless expenses.
Most people have never heard of a solenoid, and when their vehicles start having electrical problems, they automatically assume that the battery or the starter is dead.
Very possibly, it could have been the solenoid.
What Is a Solenoid?
A solenoid is just a coil of wire that's wrapped around a hollow, non-magnetic core. It receives an electric current from both the ignition switch as well as the battery.
The small electric current from the ignition switch forces the solenoid to clamp together a pair of heavy contacts. This allows the large electric current from the battery to flow to the starter and turn over the engine.
Generally, when a solenoid is broken, the two metal clamps won't operate anymore to complete the circuit, making it impossible for power to flow from the battery.
Diagnosing a Problem With Your Solenoid
If your car won't start and you've changed your battery or jumped it, and if there's no sound at all out of the starter when you turn the key, then it's a good bet that your solenoid is bad.
Depending on the solenoid, you may or may not be able to test it. Its job is simple: it connects the circuit between the battery and the starter. So when it's broken, it no longer is able to connect the battery to the starter. So testing is just a matter of bridging the connection and allowing power to flow from the battery to the starter.
If you have a metal tool with a rubber handle, you can touch both of the posts with the metal, thus bridging the connection and allowing power to flow. Just be sure not to shock yourself. This will not work in every case, however, because solenoids are different and not all of them have easily accessed ports like this.
We once had a riding lawnmower with a bad solenoid and would keep a long screwdriver in the glove box to use every time we needed to start it. We would reach in and touch the screwdriver to both the ports on the solenoid, and without fail, the lawnmower would start right up every time.
We eventually changed it out, but since the solenoid is a very simple part that only functions to bridge the connection between the battery and the starter, we figured it wasn't that big of a deal. In fact, having an easily accessible faulty solenoid is actually quite a good anti-theft system.
How Do Solenoids Break?
You car's solenoid can break for a variety of reasons. One is just normal wear-and-tear, which causes all automotive components to eventually wear out. Another factor that can cause it to go bad is poor technique in jumpstarting a car. If you've jumpstarted your car recently or helped a friend jumpstart theirs, then it's possible that you've accidentally knocked out your solenoid.
If when the jumper cables are hooked up to your battery posts, you accidentally touch the copper of the other two jumper cables together, it'll send a spike of power through your system that can knock out your solenoid.
This generally happens to the car that's doing the jumpstarting and not the one with the dead battery. Generally poor jumpstarting technique happens when a person hooks up the cables to the powered battery first, and then while walking over to hook up the dead car, the heads of the other two cables touch, thus sending a surge through the system which either knocks out the solenoid, or else weakens it so that it becomes faulty and fails at a later date.
So don't ever touch the heads of the jumper cables together.
How Do You Replace a Faulty Solenoid?
If you've gotten a faulty solenoid and you want to replace it, it should be a fairly simple process, depending on whether or not it's buried under other components.
If your electrical system is constantly acting up and you've already replaced the battery and don't know what to do, it might be a good idea to slowly start replacing the rest of the starter system.
The solenoid is a good place to start because it's a small part with little installation. If you go into your local auto parts store and find the solenoid you need for your car, they should be able to give you further instructions on how to install it.
Just make sure you disconnect your battery first so that you don't accidentally shock yourself.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
© 2011 Benji Mester
john denver on November 18, 2019:
2011 Yamaha solenoid clicks but cart wont go forward or back any thoughts
Cathie howell on July 11, 2019:
Had a new motor and new fuel pump put in my expedition, been driving it for about 2 weeks, today I drove it 30 miles when I got to where I was going I noticed smoke coming out from under my hood , it was on fire ! Got it put out with water I had , called tbeMechanic that installed the motor and fuel pump and he says it’s probably a cylinder or something like that that has nothing to do with the work they did on it sounds off the wall to me ! Can This cause a fire in your motor?
Kellie on May 29, 2019:
Please show pic o shelonoid wire
mark zwicky on March 21, 2019:
I have a 2012 Colorado 2.9 manual I had the head rebuilt when CV they put it back in the truck it will not turn over with the key. B it it will turn over if you jump the starter what is the problem?
Ryan on July 31, 2018:
Look for the fusible link coming off of the starter if that fusible link is burnt out then it will not charge the battery nor will it crank your vehicle I just had this problem on my 2005 PT Cruiser replace the fusible link with a straight wire and my problem was solved hope this info helps
cd70451 on May 07, 2018:
I have a 2008 Mercury Mountaineer 2wd v8, in which I replaced the starter and battery. I turn the key and no click or sound but I have lights, radio, everything. Surely it couldn't be the solenoid could it? It's new came with the starter.
Alan gutheie on April 08, 2018:
So my Corolla wont start an i hear nothing the starter is good changed engine relay an starter relay but still nothing. I get power to the hot wire to the starter an everything. But no sounds at all. Could that also be the solenoid?
Alexis on January 31, 2018:
I have a 2001 Cadillac deville. I have absolutely no power in my car, I can't even unlock the doors with the remote. I put the key in the ignition and nothing happens and the key will become stuck. If I connect with jumper cables to another car, I get power to lights and door locks will work and the key will turn all the way to remove. Not enough power to start though. When I turn the key over all I hear is a click. As soon as I remove the jumper cables, the car goes back to no power, no door locks, nothing. I have had the battery checked and it is good. Does anyone know what the problem could be?
Richard on November 20, 2017:
I replaced the starter and solenoid on my atv and when I went to connect the battery cable the starter came on and turned the engine over. I removed the cable and when I touched it to the positive post it arched and done the same. I replace the solenoid with my old solenoid and everything worked great. Is the new solenoid bad?
Campbell love on November 06, 2017:
Could a loose positive terminal over a period of time cause a starter motor or solonoid to stop functioning
Mindy on October 17, 2017:
I have a 2008 Chevy Impala. I have absolutely no power in my car, I can't even unlock the doors with the remote. I put the key in the ignition and nothing happens and the key will become stuck. If I connect with jumper cables to another car, I get power to lights and door locks will work and the key will turn all the way to remove. Not enough power to start though. When I turn the key over all I hear is a click. As soon as I remove the jumper cables, the car goes back to no power, no door locks, nothing. I have had the battery checked and it is good. Does anyone know what the problem could be?
Kacey on September 15, 2017:
Okay I was driving down the road and my electric went out my truck it stayed running tell I parked it and it wouldn't start back up the radio works I can hear the fuel pump kick on I hear something click on the engine when I try to turn the AC on when I turn the ignition I hear a clicking at the steering column but the horn the lights the starter nothing else works I bypass the solenoid and I hear the starter making the a winding noise I think it's the starter making the noise my solenoid is attached to my starter but it made a noise and nothing happens I tried jumping it at first nothing happened my battery is charged I've been looking for loose wires from the steering column to the alternator looked at the starter little bit I'm going to jack it up now and look better I don't know too much about checking relays what fuses I've check look good my dad tells me to take off my starter and look at it okay another thing I want to tell you maybe 6 months ago the high beams quit working I could jiggle the light switch and they would kick back on but then they quit working all together then I'll be driving with my headlights on and the dash lights go out that happened a few weeks ago and then it quit working all together to me that sounds like a loose wire somewhere but i dunno where the only thing I know left to do is jack it up and look at the starter and look for loose wires underneath it do you have any advice it would be greatly greatly greatly appreciated thank you for your time
Amber on May 22, 2017:
So I just took my car in to the shop it had been jump a little . Then died at a light was able to restart it. They told me it was my solenoid . I had it replaced. It still jumps a little and it dies more now. I took it right back to them. They told me it takes time for your car to re set it self. Is this true. It scare me to have a car and it to stop working while driving it. Any help would be much appreciated. Thank you.
Mark sells on May 20, 2017:
My problem is I got a 1982 Oldsmobile Cutlass 307 has a brand new battery brand new alternator brand new starter and brand new battery cable ends and wires put the starter on went down the road and still would not charge what is it
Devon on March 26, 2017:
Another scary thing is when your starter solenoid hangs up and your car starts on It's own without the key being on! Scared the crap out of me today when I went to reconnect the ground wire on the terminal of my battery!
Frajay on February 02, 2017:
Nice article which went straight to the point. Thanks for the write up.
Fred on December 30, 2015:
Alicia on August 08, 2015:
I have a 96 Mazda mx6 I was driving and it completely lost power I turned car off and its failed to start back up. Its not getting any spark and seems to have a odor everytime I try starting it. It sounds as if it wants to start but doesn't. Ive changed cap and rotor, still nothing. Can you guys help me I really need my car. Please and thank you in advance
Benji Mester (author) from San Diego, California on April 23, 2015:
Hey guys. Sorry, I was absent for awhile. Hope you got your cars fixed :)
Zak on June 05, 2014:
I was changing my solenoid in my mower. I'm not sure what wires go where. the new one isn't marked positive - negative?
hot rod on March 07, 2014:
i have a 1986 cutlass ciera so when i go to connect the battery terminals and i plug the negative terminal last it sparks very hard making it hard impossible to connect.
Allen Shute on June 03, 2013:
my starter wont stop
Jen on June 11, 2012:
Vr commodore just keeps dying with no power. We've changed the battery, the alternator and the starter motor ... What else could it be?
Benji Mester (author) from San Diego, California on May 01, 2012:
It definitely could be your solenoid, but I'd double check to make sure that everything's hooked up properly before doing anything more. If you're not hearing a click at all, then either your solenoid or ignition are bad, your starter is completely non-functional, or else something isn't quite hooked up right. Not too sure about the compatibility between those 2 years. I'm not an expert in older Chryslers.
earl pete on March 11, 2012:
i have the same problem when i hook my battery spark come out of neg and posi. start up ok, over nite battery . dead . dead.turn on key no light nother
Benji Mester (author) from San Diego, California on March 06, 2012:
That's not good. It's possible that your cables aren't hooked in tightly and causing sparks when the contact comes in and out. When does it spark exactly?
john on March 04, 2012:
i have sparks coming out the neg.and posi. post what is it
hemelsiddiquee from bangladesh on June 27, 2011:
Benji Mester (author) from San Diego, California on January 14, 2011:
Yeah I think you're right about it being somewhat of a mystery part. Since it has both a physical and an electrical response, it can be a bit tricky. But if the engine won't start and you use a screwdriver to bridge the solenoid ports, then you can be pretty well sure that it's your solenoid that's bad if the engine starts :)
David Walli from Northern Minnesota on January 14, 2011:
I have always considered the solenoid to be a mystery part; but if you conjectured that something was wrong and said, 'must be the solenoid', you appeared to know something about car mechanics.
Benji Mester (author) from San Diego, California on January 13, 2011:
Haha, that's awesome. It would have freaked me out as well. Sparks are always fun when gasoline is close by :)
BenjaminB on January 13, 2011:
Benji the first time a buddy of mine showed me how to do that, when my truck was having starting problems,it freaked me out completely,lol. I was afraid I was going to get the wazoo shocked out of me,but it's no big deal. It will throw a pretty good spark and scare you if you don't get the screwdriver pressed down in good contact with the frame or brush it on anything else while trying. I never actually got shocked doing it though.
Benji Mester (author) from San Diego, California on January 13, 2011:
Ben, that's an awesome tip. I had no idea you could do that. I'd like to see that in action sometime :) And that's a good tip about having a new starter on hand as well. I can see how if one system fails, the others down the line won't be far behind. I hope you've been well. I haven't seen you in awhile. I'm off to see what you've been writing recently!
BenjaminB on January 13, 2011:
Benji it's a good idea if the solenoid goes out to at least buy and have ready a new starter as well. Most mechanics will tell you that when the Solenoid goes out the starter will not be far behind. You can also jump a starter if you can get to the solenoid by arcing a long screwdriver from the positive post to the frame with the key turned in the on position. I had a semi that I started like that for over 4 months until I had enough money to replace the solenoid and the starter all in one shot.