You go to start your mower when all you hear is click…click…click or a humming sound.
A John Deere lawn mower clicks but won’t start or turn over due to loose or corroded wiring and cables; a weak or bad battery; bad ground; a failed starter solenoid, or a bad starter motor.
Follow all safety precautions found in your John Deere operator’s manual. Wear protective gloves and safety glasses for protection. Consult a professional mechanic if you feel uncomfortable working with the electrical system.
Reminder: Always disconnect the negative cable (black) from the battery before making any repairs to the electrical system.
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Follow all safety instructions provided in your equipment operator’s manual before diagnosing, repairing, or operating. Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.
This is Why Your John Deere Mower Clicks But Won’t Start or Turn Over
Damaged or Loose Battery Cables, Wiring & Terminals
Check the cables and wiring on your mower to ensure they are in good condition. Make sure the cables from the battery to the solenoid and from the solenoid to the starter are securely attached.
Inspect the cables, wiring, and terminals for corrosion that can prevent good continuity.
SOLUTION: Replace any cables or wiring that keep coming loose or are broken. Bad cables can contribute to a bad battery and starting issues.
Disconnect the battery from the mower and remove any components that have corrosion so you can clean them.
A wire brush and a baking soda mix consisting of 2 cups of water and 3 heaping tablespoons of baking soda work well. Repair or replace any wiring that has signs of corrosion.
Add a dielectric grease to protect terminals and wiring from corrosion. Replace terminals when they are damaged or in bad condition.
Bad or Weak Battery
When the battery has a weak charge, it won’t provide the power your John Deere needs to turn over and start. Check the voltage level and place the battery on a battery charger when the voltage reading is low.
If you find the battery won’t hold a charge, it’s time to replace it.
If you find you are able to charge the battery but it just keeps dying, you may need to check the charging system. Refer to the charging system section near the end of the article.
Check the voltage of a lawn mower battery
Use a multimeter’s red and black prongs and touch them to the corresponding colors of terminals on the lawn mower battery. The most common type of riding lawn mower and zero-turn lawn mower batteries are 12 volts.
You may get a voltage reading between 11.5 and 12.7. A reading of 11.5V indicates a battery that is almost dead while a 12.7V reading indicates a fully charged battery.
Charge a lawn mower battery
- Put on your safety gear so your eyes and skin are protected from acid or electrical shock.
- Get access to the battery and its terminals. You may need the screwdriver to uncover the lawn mower’s body to get access to the battery or battery casing.
- Leave the battery in its casing with the terminal cables attached.
- Connect the charging cables starting with the red cable first (The one with the positive sign on it)
- The red cable clamp goes onto the positive terminal, and the black cable clamp goes on the negative battery terminal.
- Make sure that your skin only touches the rubber coating of the charging cables and clamps.
- Set the charger’s voltage level and amp level to the desired level. The average volt level for a lawn mower is usually 12 volts. More amperage charges the battery faster (Start with two amps and work up to no more than 10 amps).
- If your charger has a battery charging gauge, keep the charger connected until the battery is fully charged.
SOLUTION: When the John Deere battery is weak, use a battery charger to charge it. If you find the battery will no longer hold a charge, it’s time to replace it with a new battery.
A battery that is able to be charged and you continually find dead may indicate you have a problem with John Deere’s charging system. See information about the charging system below.
Check the black ground cable that runs from the battery to the frame to make sure it is making good contact and is free of corrosion.
You also need to check the ground from the solenoid. A 3-post solenoid is self-grounded.
SOLUTION: Replace a damaged ground cable. Remove any corrosion found for the grounds from the battery and the starter solenoid.
Bad Starter Solenoid
When your mower keeps clicking, a likely cause is a bad lawn mower starter solenoid. The solenoid acts like an on-off switch. It is an electromagnet switch that is actuated to engage the starter motor so the engine will turn over.
Most starter solenoids are mounted on the starter. However, they do not have to be to still work. Follow the positive wire from the battery to find the solenoid.
There are many reasons why a John Deere starter solenoid can go bad. The internal spring can become weak or the copper plate can start to corrode. A bad ground, weak starter, or bad battery can also result in the starter solenoid failing.
SOLUTION: Test your starter solenoid. You’ll need a volt-ohms meter, screwdriver, continuity light, and some wrenches.
Follow the instructions found in “How to Tell Your Lawn Mower Solenoid is Bad“. If you are able to start your mower by bypassing the solenoid, it must be replaced.
Bad Starter Motor
If you’ve checked the battery, cables, wiring, ground, and starter solenoid only to find them in good condition, but still have a starting problem, your starter may be the problem. The starter can be removed and tested.
SOLUTION: A starter can be a pricey item on a lawn mower. I advise having your local dealership confirm you have a starter motor problem before you replace it.
You can also bring the starter to a local repair shop that specializes in starter and alternator repairs. The personnel at the repair shop can test the starter and oftentimes rebuild it if necessary.
Bad John Deere Charging System Drains the Battery
A bad charging system on a mower will not keep your battery charged and in turn, cause a weak battery to not start your mower.
Depending on the size of your lawn mower, it may have an external alternator like the one you find on a car. It may also have an internal one located under the flywheel. Most John Deere lawn mowers will have an internal alternator.
Perform the steps provided here to check the charging system using a volt-ohms meter.
If you find your lawn mower is no longer charging the battery, I recommend having a mechanic familiar with your charging system perform further tests and necessary repairs. Troubleshooting the exact cause of a charging system can be quite difficult.
If you’re not familiar with the charging system, you will probably just end up throwing parts at your mower.
This can get very expensive, especially since if you get it wrong, you can’t return an electrical part. You could be looking at a bad stator/alternator, regulator, or other electrical problem.
Still Having Problems with Your John Deere Lawn Mower?
As a John Deere owner, you will encounter a variety of problems over the life of the equipment. These can include problems with starting, dying while mowing, vibrating, cutting unevenly, and not moving.
To help you identify the reasons your mower is having problems, I put together a handy guide to help you troubleshoot your mower. Check out Common John Deere Lawn Mower Problems and Solutions.