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What Does a Winch Solenoid Do?

Off-road enthusiasts usually have vehicles with all the bells and whistles needed for backcountry adventures. One piece of necessary equipment is a winch, which can get you out of tight situations or help others in a rough spot. But a working winch is only as good as its solenoids. You don’t want to get stranded by a bad solenoid (been there), so it may be time to learn about your winch solenoids.

We will also discuss what you can do if your solenoids fail on the trail. Let’s get started!

What Is a Winch Solenoid? 

A winch solenoid is an electronic device that activates the motor on a vehicle winch. Its basically a large electronic switch that operates from a smaller “signal” switch. This smaller switch can be mounted wherever the winch is controlled from or even a wireless controller.

Winch not working? Here's how to test the solenoid #1471

So What Does a Winch Solenoid Do?

Before we answer this question you need to know what a solenoid is. A Solenoid is just an electrically controlled switch. They are usually used to take a small control signal and turn it into a large flow of power. They can be controlled by a manual operator or a computer circuit.

As an electromagnetic switch, the main job of a winch solenoid is to allow current to flow to the motor. Because winches tend to use alot of power, they need a lot of current. This requires very large wires. These large wires would not make sense to run all the way to the control for the winch, so instead the solenoid uses a small amount of power (from the control switch) to pass a much larger amount of power to the motor.

The winch motor uses the energy to turn the winch drum. Winches commonly use a separate solenoid for each direction the winch turns. However, some larger ones will use two solenoids for forward motion and two for reverse. Many times these multiple solenoids are actually contained in a single unit called a “solenoid pack”.

warn winch solenoid pack
This is our Warn winch solenoid pack. (during a rebuild) It can control forward and reverse directions. The big studs on the top go to the motor and the small connections on the side go to the control.

What If a Solenoid Fails On The Trail?

So we have actually experienced this. Since most winches use at least two solenoids (usually 4) its likely that only one will fail. It’s even more likely that you don’t actually have a bad solenoid but a corroded terminal. Either way, the failure will most likely cause the winch to work in one direction and not the other. Because the retract direction uses a lot more power this is the most common direction to fail.

So what do you do? Well, the easiest thing is to just reverse the motor leads and what we did. Our winch would work in the out direction only, so we just reversed the leads so we could winch in. Then we just put the winch in the freewheel and pulled the rope manually. Of course, reverse control is one of the benefits of a winch, but losing that is better than losing the ability to pull in. When you reverse the motors the winch will work backward with the controls (in is out and out is in) but you are also using the opposite solenoids so you can usually get it to retract.

If you can access the solenoid pack you could open it up, pull the solenoid leads and clean them, but this is a lot harder to do alongside the trail. In fact, our winch is built into the bumper and we could not access the solenoids without removing the winch altogether so the motor leads are all we could do.

Here’s a shot of our motor leads. Warn usually has three motor leads and ground. If you are using a warn reverse F1 and F2 to reverse the solenoid direction.

warn 16.5ti motor leads
Once we got back and were able to pull the winch this is what our motor looked like

Do You Have to Use a Solenoid On a Winch? 

Yes, a solenoid helps control the electricity going to the winch motor. Without one, the motor and winch switch could burn out repeatedly. You can, however, temporarily wire around a faulty winch solenoid until you can replace it. Rewiring for this purpose is only a stop-gap until you install a new solenoid, as you could damage the motor without it. Remember, a solenoid is much less expensive to replace than a motor.

Pro Tip: We took a closer look at What Is a Winch? How They Work and Components Explained. Check it out!

Close up of truck bumper with winch in place.
Before you start off-roading, test your winch solenoid first to make sure it is in tip top condition

How Do You Test a Winch Solenoid? 

If you are diagnosing a problem with the winch and want to eliminate the solenoid, it is convenient to test. First of all just listen for the solonid to click. They usually make a click sound when they engage, so if you do not hear the click first check that you have voltage from your control to the solenoid control inputs when switching it on. If you have voltage then you need to check the output.

With the winch off, use a voltmeter, attaching each probe to the two large studs on the winch side of the solenoid that goes to the motor. The meter should read 0 volts if the solenoid is working correctly. Now engage the winch and read the voltage, if you are getting 12V (if it’s a 12V unit) then the solenoid is working. If not, it may be time to check the wiring or replace the solenoid outright.

Close up of installed winch on vehicle
Keep an ear out for a clicking sound from your solenoid to determine if it is working well.

Why Does My Winch Solenoid Just Click?

If your winch won’t start but clicks, it is likely related to one of three causes. The first thing to check is your cables. They may not be making contact, so clean them and check their connections.

If the cables seem to work correctly, here’s a test to single out if it is the motor or the solenoids: put the winch in a free spool and disconnect the positive lead from the battery, leaving the ground wire attached. Most winches have three posts on the motor, for the positive. By reversing the leads between two of the posts the motor reverses. The most common labeling is A, F1 and F2 on these posts.

common winch wiring
Most winch motors have 4 wires like this.

Disconnect and label (A, F1, and F2) the three cables that run from the control pack to the posts on the motor. Take a jumper wire and attach it from A on the motor post to F1 on the motor post. Then use jumper cables to give the battery power. The winch should work in one direction. Complete the same exercise by attaching A to F2 on the motor posts to see if the motor functions in the opposite direction. If both run, the motor is fine, and your problem lies with the solenoid.

There may be two or four solenoids in your winch, so change out all of them, and you should resolve your clicking problem.

Pro Tip: Make installing your winch quick and easy with this guide on How to Mount a Winch on a Trailer: Beginners Guide.

How Do You Replace a Winch Solenoid? 

If your solenoid needs replacing, start by taking off the solenoid cover and drawing a simple diagram of the wiring. It’s also a good idea to take a few pictures of how it’s wired and label the wires. Then disconnect the Plus wire at the battery, and then remove the smaller gauge control wires. Next, remove the larger gauge wires and any jumper wires. After removing the wires, the solenoid should come out by twisting and lifting it.

Replace with the same solenoid and re-wire the same way. Make sure to leave the positive disconnected from the battery until all solenoid wiring is complete.

replacing winch solenoids
Once you have your solenoids exposed, replacing them is a like for like process. just put it back to gether the way it came apart.

How Do You Hardwire a Winch? 

If you must temporarily bypass a faulty solenoid, you can do so by gaining access to the solenoid wiring (take off the solenoid cover). Find the big red jumper cable labeled + Battery and attach one end to the red + Battery terminal and the other end to your forward (F1) or reverse (F2) terminal. The motor will run, so to turn it off, you will have to disconnect one end of the big red jumper cable. 

Our winch had a solenoid fail in the retract direction once. Because this is usually more critical than the extent, we just swapped the wires on the solenoid to reverse the motor. It ran backward of the control indications, but worked well and got us back on the road.

Either jumping the winch or swapping the forward and reverse solenoids might work well to get you out of a sticky situation where your winch has failed you. But dont rely on these methods long term.

Pro Tip: A winch isn’t the only thing you need for going off-roading. Make sure you pack these 11 Top Essential Gear You Need For Overlanding.

We Renovated A 20 Year-Old Truck Camper Into A Luxury Overland Vehicle

Why Do I Need a Solenoid?

A solenoid keeps your winch motor and switch from overheating and incurring damage. Without it, you will have some expensive repair costs and a winch that cannot operate correctly. Ensure your winch solenoids are in top-notch working order by testing your winch before hitting the road so you don’t get stranded without a working winch when you need one.

Have you ever had to replace a winch? Tell us about your experience in the comments!

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About Tom Morton

Tom, a Pacific Northwest native, is our technical genius. Born in Washington and raised in Alaska before settling in Michigan. He's the man who keeps our operation running, both figuratively and literally.

With a background in Electrical Engineering, Tom specializes in RV solar systems and lithium batteries. He made history as the first documented individual to use a Tesla battery module as an RV battery. Tom has personally assisted countless RVers with system installations and has educated thousands more through his videos and articles.

Cinematography is another of Tom's passions, showcased in his work on the Go North series. You can see his camera skills on display in The RVers TV show on Discovery Channel and PBS where he also stars as a co-host.

Tom's mechanical expertise extends beyond RVs to boats, planes, and all things mechanical. He's renowned for taking on maintenance and repair projects single-handedly and is often spotted underneath RVs, making him the technical backbone of our endeavors.

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