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Hayes Electronic Sway Master


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Installed a Hayes Electronic Sway Master on our Elite II. Did not have any stability issues with the Ollie/Tundra rig before installation. Installed the Sway Master because the Tundra’s manual requires a trailer sway device when the trailer is over 2000 pounds. The Sway Master uses trailer brakes to dampen trailer sway movement.


Since the ready to camp weight of our Ollie is under 5000 pounds with less than 500 pound tongue weight, with black, grey, and fresh water tanks empty, I'm not using a WDH for now. The Tundra Manual requires WDH when towing trailers over 5000 pounds. Weighed the Ollie and Tundra at the local county landfill scales.


Some folks may be considering installing the Hayes Sway Master on their Ollie. Please contact Hayes to be sure the Sway master will work with your brake controller and tow vehicle.  Also contact Hayes to be sure you are orienting the Sway Master as recommended and with technical questions, too.


Testing the Hayes electronic Sway Master on the Ollie earlier this week. This unit dampens sway quickly using trailer brakes, very impressed with this unit, so far.


I'm not a mechanical engineer and cannot say this is the best way to install the Sway Master since I'm not a professional trailer technician, either. This is how I decided to mount this sway control.  Used 1 1/2" X 1 1/2" aluminum angle 3/16" thick to mount the Sway Control without drilling additional holes in the Ollie hitch.


Did not shorten the original Ollie 7 pin cable or Sway Master 7 pin cables for this installation.  Plug in the Ollie 7 pin cable into the Sway Master to start operation, also need to unplug the Ollie 7 pin cable after each use.


Like always, I take too many photos:


180 Degree turn clearance check:


Excess Sway Master 7 pin cable:


Excess Ollie 7 pin cable:


Finished Project:




Hayes Sway Master Youtube Video:



Etrailer Sway Master Youtube Video:


Bill & Debbie / 2015 LE2 #75 / 2022 Tundra / North Carolina


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Since the unit uses a GPS receiver to determine trailer speed, do you have any concerns about it working correctly when the sky is obscured, say by heavy tree cover or terrain (cliffs or steep mountains). It seems as if the unit would be great on Interstates and wide open highways, but maybe no so great in the mountains or forests. All my GPS devices work great in Eastern WA but they can get confused when I go to the west side of the state, where there are lots of pesky trees and very heavy cloud cover.


Is there a built in way of showing you that the system is actually online and working?


I think that relying on GPS for a critical safety device to work correctly is a little bogus. Why not a simple speed sensor that uses magnets mounted at a wheel hub?


John Davies


Spokane WA



SOLD 07/23 "Mouse":  2017 Legacy Elite II Two Beds, Hull Number 218, See my HOW TO threads: 

Tow Vehicle: 2013 Land Cruiser 200, 32” LT tires, airbags, Safari snorkel, Maggiolina Grand Tour 360 Carbon RTT.

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Why not a simple speed sensor that uses magnets mounted at a wheel hub?




I'll use the Hayes Sway Master and you can use speed sensors/magnets. With the great towing manners and stability of the Ollie, this system probably will not be needed, but will be there just in case.

Bill & Debbie / 2015 LE2 #75 / 2022 Tundra / North Carolina


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Why not a simple speed sensor that uses magnets mounted at a wheel hub?

John, I’ll use the Hayes Sway Master and you can use speed sensors/magnets. With the great towing manners and stability of the Ollie, this system probably will not be needed, but will be there just in case.



You didn't answer John's concerns at all.  He has a real point in wondering if GPS might be obscured and the system not work when needed.


The GPS system makes it easier to install because you don't have to do anything other than plug it in, but GPS is not always available.  I don't know why they chose 45 MPH as the turn on point.  It did need some indication of speed to not be on all the time and drain the battery, I guess, but it really only needs to sense sway in order to operate.  Sway is a simple repetitive motion that can be sensed easily.  It also seems to simply apply both brakes when it senses sway and that is something the driver can easily do with any brake controller.


My Ollie is very stable, but if it did get into trouble, I'd simply apply the trailer brakes manually to settle it down.  Then figure out why it happened and correct it.


"I only exaggerate enough to compensate for being taken with a grain of salt."

LE2 #92 (sold),   Black Series HQ19   

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So as I understand it, this controller applies the trailer brakes when it detects sway; i.e., it does the same thing as manually applying the trailer brakes via the brake controller, but does so automatically.


I'm curious if modern brake controllers don't do the same thing - it's not clear to me on the F150, for example, whether the truck's brake controller and sway control software are linked.   Reading about it, it seems like the brake controller controls the trailer's brakes while the sway control acts only on the truck's brakes & steering.  I could be wrong, though, and it could be that the sway control will instruct the brake controller to apply the trailer's brakes if it detects sway.  I mean, you'd think it would do that, right?  I guess like Bill said, you'd better check with Hayes to make sure this thing is compatible with your truck, so that you don't end up with two systems trying to accomplish the same thing.


Just generally, are there any situations where this might be a disadvantage?  Would it get confused if being bumped around on a gravel road?  What happens if you're braking on a curve and the trailer started to step out - would this unit interpret that as sway and lock up the trailer's brakes?


Bill, did you look at any other brands before buying this one?  If so, what made you choose this one over any other?


I'm curious about the GPS thing, too.  For the most part, I think that in the situations where you found yourself without a GPS signal that you'd probably not be going fast enough to need this unit, but I can also imagine some situations, like mountain passes, where you might be at highway speed and a signal is spotty.  My guess is that in those situations, it would simply shut off and so wouldn't cause any harm.

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With a bit of searching around, I did find this which would indicate that the Ford integrated brake controller does indeed do the same thing...

In 2009, Dodge and Ford introduced trailer sway control on their new light-duty pickups. In the Dodge Ram 1500, its stability control system was enhanced to automatically counteract unintended trailer motion by using the truck’s antilock braking and traction control systems to apply individual wheel brakes and/or reduce engine power. It works by asymmetrically applying brake pressure on the tow vehicle’s opposite side to counteract sway.


The Ford F-150 uses a more sophisticated trailer sway control system. By taking advantage of its integrated trailer-brake controller and roll stability control,
the F-150 can apply both its own brakes and a trailer’s electric brakes without the driver's intervention to stop sway when the vehicle senses excessive rear yaw input from the trailer.

That was written by Mike Levine, who is Ford Truck's media guy - though this was written in 2010, so he might not have been at Ford at that time.  It's strange because nothing on Ford's website or informational videos on sway control mention anything about activating the trailer's brakes.



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I think we all have a few considerations we need to evaluate as a part of this thread.


1. Some TOW vehicles are later models and may have more or less technological advances than others.  Some manufacturers may have additional requirements in the owners manual that may be based upon technological advances, litigation or future adaptions that the aftermarket will provide at a cost.


2. Many times I find that the accessories, safety features and additions we put on our TOW or Oliver is based upon personal preference.  It is somewhat dangerous to make absolute statements because there may be a different and sometimes more innovative approach to a problem.


As examples, I have a 2003 Toyota Tundra that is a perfect TOW in many ways for my Oliver.  However, it did not come with a brake controller or Sway control.  There is a clause in my owners manual that requires / reccomends both.  My son in law occasionally borrows my trailer and his 2014 GMC TOW has almost the same verbiage in his manual.   I personally choose to add a sway control whether needed or not.  I drove my Oliver across the U.S. without a sway controller and despite strong winds across Oklahoma, Texas and New Mexico, big tractor trailers, buses and Pusher RVs , I had no problem with my Oliver or TOW.  However, because of the litigious society we live in, I choose to add this to offer some level of protection in the event of a lawsuit.  If the manufacturer of my TOW has it in writing and I am in a accident with my Ollie (shutter !) I believe I would have some element of legal protection in the event an attorney for the plaintiff chose to use the sway controller as an issue.  We all choose to approach problems differently.  The good thing about this forum is that from a personal standpoint I have learned so much and appreciate the well intended advice of others via this forum.  Thanks for consideration of everyone's opinion, needs and preferences when sharing in the forum.



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I agree.  If I had a tow vehicle that didn't have sway control at all, I would certainly put a unit like this one on my list of essentials.  Especially if the vehicle's owners manual recommends it.  If nothing else, it's inexpensive peace of mind and looks very easy to install.


If your vehicle does have sway control, I think you'd want to do a bit of research to see if this controller wouldn't be duplicating something that your vehicle already does.  The F150 is top of my list, so I'm probably good, though I'd like some better verification that the sway control will indeed brake the trailer.


By the way, as far as attaching this to the trailer goes, I wonder if this wouldn't be a good use for VHB tape.  That way you could attach it directly to the frame without drilling while eliminating that extra 1 ½" in width.

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Please check your tow vehicle operators manual and contact Hayes if you have any questions if the Sway Master will work with your tow vehicle and Ollie.


Hayes replied to the question about loss of Sway Master GPS signal and to how the unit will operate in that situation.


Hayes Reply:


"If the GPS is not connected, the Sway Master will go into a default mode. This means the unit

will activate when sway is detected regardless of speed. So no matter the connection status of the GPS,

the device will still combat sway".

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Bill & Debbie / 2015 LE2 #75 / 2022 Tundra / North Carolina


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