John Deere PTO Switch Bypass: Simple Tips

John Deere lawn tractors and zero-turn mowers are certainly the crème de la crème of the industry across various dimensions. Effectiveness, efficiency, comfort, technological innovation, and, most importantly, safety. While we always recommend “safety first”, this article is for those who are looking for a way to temporarily bypass the PTO switch.

Mower decks normally will not spin the blades while a John Deere riding mower is in reverse. In order to test the operation and functionality of some parts, it may be necessary to bypass the safety of the PTO switch that causes this. The switch should be replaced after testing is completed.

Hop on, as we detail the process of bypassing your Deere mower’s PTO switch, which can save you an unnecessary visit to an overcharging “expert”. We will also answer some FAQs around this topic. Let’s go!


Do John Deere Mowers Have A PTO Switch Bypass

The PTO (or “power take-off”) switch is one of the safety switches on Deere riding mowers. It regulates the operation of various implements, the most common of which is the mower deck.

Under normal circumstances, most Deere tractors and zero-turns don’t allow the operator to reverse the machine while a PTO implement is in operation. Switching to the reverse gear will cause the implement to shut off for safety reasons.

Because of shockingly high mower accident statistics, a lot of manufacturers thought it would be a good idea to add such features…which is understandable.

Due to this it is only advisable to bypass a PTO switch for testing and repair.

Again, while safety is of the utmost importance, it is not always convenient. Being able to test mow while reversing your garden tractor, for example, would save you time and fuel.

Some Deere tractors have additional switches for engaging implements while reversing, but those need to be engaged every time you want to reverse…which can get annoying. 

This is where bypassing comes in. Bypassing is the overriding of the machine’s factory mechanical and electronic systems. When it comes to PTO, bypassing cuts off the regulatory measures on all power take-off implements, including mower blades.

What Does A PTO Switch Do?

A PTO switch works together with the PTO clutch to engage or disengage any PTO implements. The deck and blades are the most common PTO implement for Deere riding mowers. Activating the switch channels some of the engine’s power to the deck and makes the blades spin. De-activating the switch cuts off this power transmission and stops the blades.

The clutch system consists of an upper and lower plate. The upper plate is sat directly below the engine’s drive pulley and it houses a large electromagnet on the inside. The lower plate is a flat metal disc that has a large mower deck pulley attached to the bottom. 

Sandwiched between the two plates is a rotor, or “flywheel”, that is powered by the engine crankshaft. When the engine is running, the drive pulley spins this shaft, which spins the flywheel. 

When the operator activates the PTO switch, an electrical signal travels down from the switch to the upper plate and activates the magnet. When this happens, the lower plate gets attracted upwards and latches on to the spinning flywheel. This is possible because the magnetic force can travel through the gaps on the flywheel.

Once attached to the flywheel the lower plate and, ultimately, the mower deck pulley also begin rotating. This causes the mower’s blades to spin. Cutting off the switch turns the magnet off, which drops the deck pulley from the spinning rotor.

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How Do I Know If My PTO Switch Is Bad?

Testing PTO switches is pretty simple. Electronic PTO switches are tested by using a multimeter to check resistance between the switch’s pins. The multimeter must be set to the Ohms setting.

An electronic PTO switch is made up of a knob and a housing case with several pins protruding from the bottom. John Deere’s switches usually have eight pins (two rows of three, one row of two). One outer bank of pins is known as the “normally closed” (NC) side while the other outer bank is known as the “normally open” (NO) side.

To test…

  1. Start with the switch in the “off” position and place one multimeter lead on a NO pin.
  2. Place the other lead on the NC pin that is directly opposite to this NO pin.
  3. If the multimeter beeps and displays values, the link between the two pins is fine.
  4. Repeat this process for all outer bank pins.
  5. Next, set the switch to the “on” position.
  6. This time, place one lead on an NC pin and a corresponding pin in the middle row, not the NO row.
  7. Repeat this for the other middle pin. There’s no need to worry about the extra pin.

If the test yields “beeps” all the way through, then the switch works. If there is no beep or screen reading when there should have been, you should repeat the test. If the switch fails again, you can be sure it’s not working and needs replacing.

John Deere PTO Switch Bypass – Simple Tips

The process of bypassing the PTO switch is pretty simple for all Deere mowers. The aim is to access the PTO safety switch.

What You Need To Know To Start

Depending on your mower model, you will need a Phillips head screwdriver, an Allen wrench (probably 3mm), and a socket wrench to remove a panel covering the safety switch and other components. This panel is under the seat on zero-turns and some garden tractors.

PTO safety switches on some garden tractor models (such as the 100 series) are under the hood. Regardless of the model you have, you are likely to find the safety switch near the battery, its main power source. 

For machines with PTO safety switches under the seat, you should use the aforementioned tools to remove bolts, nuts, and washers holding the cover panel in place. You may even have to remove some seat adjustment knobs. Other machines only need require you to open the hood as you normally would. 

If your riding mower’s PTO engagement switch is a push/pull knob, chances are the PTO safety switch is operated by the mower’s transmission mechanics. These kinds of mowers have a feature known as Reverse Implement Operation (RIO), which must be engaged every time you switch into reverse.

When the machine is in neutral or in drive, a metal bar stays pressed against the button on the safety switch. This completes the PTO circuit to allow the mower deck and other implements to work. 

Switching to reverse causes the mechanism to pull the metal bar away from the switch button, which releases it to cut off PTO. This is why the mower deck disengages and cannot mow when the machine is reversing. It’s installed because, understandably, the manufacturer assumes that it’s not always easy to see where you’re going while reversing.

On mowers where the mower deck is engaged and disengaged with a lever on the dashboard, the PTO safety switch button is pressed by a metal bar linked to the mechanics of the lever itself, not the transmission. 

The button on the switch (and PTO) is engaged when you move the lever to the “on” position. Switching to “off” will pull the bar away from the button to cut off PTO.

Tips For Bypass

Here again, it is best to leave the bypass in an operational state. These measures should only be used in most circumstances for repair and testing.

In either case, the solution is the same. Simply pull the safety switch out of position, while being careful not to yank out any wires. Next, tie a zip-tie along the length of the activation switch and tie down the button. The zip-tie must be snug against the button to ensure it remains pressed down. This ensures PTO remains engaged while reversing.

Finally, put the safety switch back in position, cover up the mower, and test it out.

The Final Touches On A John Deere PTO Bypass…

If you are being safe and bypassing the PTO switch for repair or testing, then these tips should help you. Just make sure not to run your John Deere mower in this way for normal mowing.

These PTO switches though inconvenient in some instances has saved many of us as professionals from loosing appendages. Be safe and use all safety measures so you can enjoy your mower and landscaping activities for years to come.

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Mathew Booe

Mathew has worked in landscaping professionally for over 10 years. He is a grandpa and frequently interviews other experienced landscapers and lawn care experts who are also grandpas for these articles.

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