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Roadmaster Automatic Battery Disconnect with Switch for Towed Vehicle w/ Supplemental Braking System

Roadmaster Automatic Battery Disconnect with Switch for Towed Vehicle w/ Supplemental Braking System

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Roadmaster Auto Battery Disconnect Accessories and Parts - RM-766
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Conveniently disconnect your battery so that your vehicle can be flat towed per manufacturer instructions. System with switch charges your towed car's battery during towing to prevent dead battery and maintain charge for accessories. 1-800-496-5010 to order Roadmaster accessories and parts part number RM-766 or order online at Free expert support on all Roadmaster products. Great prices and Fastest Shipping for Roadmaster Automatic Battery Disconnect with Switch for Towed Vehicle w/ Supplemental Braking System. Accessories and Parts reviews from real customers.
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  • Reviews (171)
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Roadmaster Accessories and Parts

  • Tow Bar Wiring
  • Auto Battery Disconnect
  • Roadmaster

Conveniently disconnect your battery so that your vehicle can be flat towed per manufacturer instructions. System with switch charges your towed car's battery during towing to prevent dead battery and maintain charge for accessories.


  • Lets you easily disconnect your battery so that your vehicle can be towed behind your RV
    • Can only be used on vehicle on which battery must be disconnected for towing
    • Includes switch for installing in the towed vehicle
    • Consult your owner's manual
  • Eliminates inconvenience and the potential danger of pulling your battery cable
  • Operates with switch
  • Includes a corrosion-resistant, marine-grade solenoid with 200-amp constant duty and 600-amp surge
  • Works with almost any 12V battery
  • Comes pre-assembled for easy installation


  • Disconnecting the battery, whether manually or with the Roadmaster automatic disconnect, will affect your vehicle's electronics. You will need to reset various electrical components in your vehicle following use of this product.
  • Not for use with diesel engine vehicles, due to the high compression ratio of diesels the engine can surge up to 10 times that of a gasoline engine at start up and can cause the solenoid to fail.
  • A charge line, (RM-156-25 - sold separately), is a good idea if you have a braking system that is using power from the towed vehicles battery while it is disconnected.

766 Road Master Automatic Battery Disconnect

Replaces 765

Item # RM-766

Installation Details RM-766 Installation instructions

This Product Fits The Following Vehicles

Customer Satisfaction Score:

Customer Reviews

Roadmaster Automatic Battery Disconnect with Switch for Towed Vehicle w/ Supplemental Braking System - RM-766

Average Customer Rating:  4.8 out of 5 stars   (171 Customer Reviews)

Conveniently disconnect your battery so that your vehicle can be flat towed per manufacturer instructions. System with switch charges your towed car's battery during towing to prevent dead battery and maintain charge for accessories.


This product works great for our 2018 Ford Explorer. It works perfectly for our application and allows us to easily disconnect the vehicle battery when we are preparing to tow the Explorer.


The battery disconnect installation instructions were clear and the installation went well in my 2018 Chevrolet Colorado ... in spite of the kit missing a few pieces like a second star washer for connecting the two battery cables and the second piece of protective tubing. I covered the exposed energized solenoid terminals with electrical tape to prevent an potential inadvertent short in the future when working under the hood. Works as designed so far.

I towed the Colorado from Maine to Arizona last winter and the battery disconnect worked well for the entire trip. It made preparing the truck for towing and driving very easy!
Mike - 07/01/2020


This unit DOES NOT work with a diesel motor. When I asked for a complete assembly, this should not have been sent.
I need to return this item.

I sincerely apologize if this was recommended to you for your diesel motor. I will have our customer service reach out.
-- Etrailer Expert Jenny N - 09/07/2022


I received the Roadmaster remote battery disconnect in a timely manner and had it installed in my 2016 Chevy Colorado by a local RV dealer. I used it for the first time this week and it worked like a charm. I didn't lose any of my preset radio stations or any other data that I know of. Pushing a button on the dash is a lot easier than disconnecting and reconnecting battery cables.

Still working just fine.
Robert M - 09/09/2017


The RM-766 is a solid piece of hardware and comes with absolutely everything required for the install, right down to the "Tow" and "Drive" stickers for the switch. I use it to disconnect the battery in my 2016 Ford Edge 3.5L AWD, to help make it flat towable behind my RV. It works great and I do not have to open the hood and mess with battery cables while travelling. I like it.

There have been absolutely zero problems with this switch so far. Works like a charm.
Herbert M - 07/13/2018


Very good braking system, battery switch, nice easy to use thanks John H


The service and support staff was knowledgeable and extremely attentive to my questions and concerns, they were quick to solve my problems. Top of my recommendation list.


Arrived on schedule today and installed today, In stallation videos for my vehicle were excellent


I have a 2014 Silverado that I wanted to tow with my RV. In order to tow GM calls for the battery to be disconnected. This was the only product that I fond that would do what I wanted. It is slightly over priced in my opinion but it does the job. I have attached it to my aftermarket air box and ran the switch under the hood release. This way I can use the remote to unlock the doors when I am ready to unhook.


Love the ease of battery disconnection with this product. The electronics in my 2021 Silverado seem to hate being without power though, and the remote keyless entry is a little finicky for a few cycles after power is restored, by that’s a Chevrolet issue.


Item as listed


The product was as advertised and the delivery was also as promised. The order staff was very helpful and knowledgeable about the product and which model to order. The tech support was also very helpful and seemed to know the product and exactly what steps to take for a successful installation.


LOVE IT!! Most of my other friends do not have the disconnect on their vehicles and have to deal with dead batteries and running their tow vehicle engines every couple of hours.


Didn't need it, returned it.


Quite a bit of work to get it installed into the Chevy Spark. But it does work nicely.


Pain in the rear to install but got it installed.


always great service!


making towing and keeping battery up, what could be better?


Easy install


Everything works amazing
Thanks to all
at etrailer


Works exactly as advertised. Shipping was fast and well packed. Recommend


missing on off button

I will have our Customer Service team reach out to you.
-- Etrailer Expert Jenny N - 06/03/2022


Easy to install and did what it was supposed to do


i've been towing my gmc canyon for the past year .we have gone to ky., mn.,fl.,and mo. with no problems. the towing package i bought was and easy install and took just a few hours by following the instructions. it was money well spent.

lupe v - 04/04/2021


I gave each and every one of the items I purchased a 5star rating because they each have contributed greatly to my confidence and sense of security about full-time RVing in my Class C rv towing my little car behind. Each product has been well made and thought out and the service from etrailer has been great....from price to shipping and packaging. I couldn't be more pleased with everything. Job well done. Thank you.

Show More Reviews

See what our Experts say about this Roadmaster Accessories and Parts

  • Does Installation of the Roadmater RM-765 Auto Battery Disconnect Charge the 2008 Honda CR-V Battery
    The Roadmaster Auto Battery Disconnect, item # RM-766, includes all of the parts needed for installation on your 2008 Honda CR-V, and supplies a trickle charge from the towing vehicle to the towed vehicle battery when properly installed. You will not need to remove the fuse for flat towing if the battery disconnect is installed on your vehicle.
    view full answer...
  • Using Roadmaster Automatic Battery Disconnect # RM-765 When Flat Towing 2011 Jeep Wrangler
    First and foremost, if Jeep requires the battery to be disconnected while flat towing, you must follow these instructions in order to prevent damage to your vehicle. The main reason for disconnecting the negative battery cable when flat towing is to prevent the battery from draining. When you flat tow your Wrangler, the ignition must be left in the ACC position. This would leave certain electronic components on that could drain the battery. The benefits of using the Roadmaster Automatic...
    view full answer...
  • Installation of Roadmaster Auto Battery Disconnect # RM-766 on 2009 Hummer H2 With 5-Way Connector
    Since the battery must be disconnected when flat towing your 2009 Hummer H2 an option is to use the Roadmaster Auto Battery Disconnect, part #RM-766. The disconnect is activated by the taillight circuit from the tow vehicle. When the tow vehicle taillights are on, the solenoid is activated and the Hummer battery is automatically disconnected. The power from the taillight circuit that is not needed to keep the solenoid open is then routed to the Hummer battery helping to maintain the charge...
    view full answer...
  • Key Position for Flat Towing a 2014 Jeep Wrangler Sahara
    Different vehicles have different requirements and procedures for flat towing. In order for your 2014 Jeep Wrangler Sahara to be flat towed, and really any vehicle, the steering wheel has to be unlocked which requires a certain key position. An automatic battery disconnect, # RM-766, is not a requirement to flat tow your Jeep. But if using a supplemental braking system, required in most states by law, and if it requires 12 volt power, you could install a 12 volt outlet kit, # RM-9332....
    view full answer...
  • Installing Roadmaster Automatic Battery Disconnect with Switch on 2015 Chevrolet Silverado 1500
    When installing the solenoid for the Roadmaster Automatic Battery Disconnect with Switch # RM-766 on your Chevrolet Silverado, you will just want to find a spot under the hood, within reach of the battery. Also keep in mind that the solenoid will need to be grounded, either by attaching it to a metal surface or by using the included white ground wire. One red cable, which will be labeled "battery post" coming from the solenoid will go to the positive battery post in your vehicle. The...
    view full answer...
  • Installing Roadmaster Automatic Battery Disconnect with Switch on 2016 Chevrolet Colorado
    According to the online owner's manual for the 2016 Chevrolet Colorado, you will need to disconnect the negative battery cable at the battery and secure the nut and bolt before flat towing the truck. It states that failure to do this may cause damage to the vehicle. When installing the Roadmaster Automatic Battery Disconnect with Switch # RM-766 referenced in your question, you will first follow the vehicle manufacturer's instructions to disconnect the negative battery cable. Then from...
    view full answer...
  • Recommended Battery Disconnect For 2015 GMC Yukon Being Flat Towed
    When flat-towing your Yukon, GM does recommend you disconnect the battery which would then allow you to be able to put the key in ACC mode and allow the steering to turn without locking up. Since the ACC mode is the only method available I recommend a battery disconnect like the Roadmaster Automatic Battery Disconnect for Towed Vehicles, part # RM-766. This automatically disconnects the battery in your Yukon when the motorhome lights are turned on and saves you time with physically disconnecting...
    view full answer...
  • Will the Brake Buddy Battery Maintainer work with Battery Disconnect RM-766
    The Battery Disconnect part # RM-766 installs on the positive battery wire so that when activated all power is cut for the vehicle. See attached chart. What you would need to do is install the # RM-766 after the connection you have for your Brake Buddy so that it can still draw voltage when needed even if the # RM-766 is activated.
    view full answer...
    Image 1 for
  • Disconnecting Battery in 2015 Chevy Colorado When Flat Towing
    The main reason that the battery must be disconnected when flat towing is to prevent the battery from draining. When flat towing your 2015 Chevy Colorado, the key must be left in the (II) position. This would leave some of the electrical components on and drain the battery. To eliminate the hassle of having to disconnect your battery each time you want to flat tow, I recommend installing the Roadmaster Automatic Battery Disconnect, part # RM-766. The automatic battery disconnect is activated...
    view full answer...
  • Recommended Battery Disconnecting Switch For 2016 Ford Edge
    You can run a hot line from your motorhome to your battery. It will maintain your battery to an extent but hard to know what the power draw is on your battery and whether that hot lead would charge enough to still keep your battery charged enought to start following your trip. Your vehicle relays and fuses will protect your computer and electronics. I recommend the Roadmaster Automatic Battery Disconnect with Switch for Towed Vehicle w/ Supplemental Braking System, # RM-766. This will...
    view full answer...
  • Using Roadmaster Automatic Battery Disconnect RM-766 When Flat Towing 2017 Ford Explorer
    Some vehicles require disconnecting the negative battery cable when flat towing them to prevent battery drain. If you have installed the Roadmaster Automatic Battery Disconnect # RM-766 you will not need to do this since this item includes a switch to select either Tow or Drive modes. It will deliver a trickle charge to your toad's battery. Please refer to the linked installation video showing another Ford vehicle.
    view full answer...
  • Why Remove the Negative Battery Terminal First When Installing a Automatic Battery Disconnect
    By removing the negative battery cable you are disconnecting the battery from the chassis of your vehicle. If you begin to remove the positive side before the negative and your wrench would make contact with any part of the vehicle, then you could cause a short in the system. This could in turn blow fuses and relays or even damage some of the sensitive electronics on your 2016 Chevrolet Tahoe. Roadmaster specifies that the Automatic Battery Disconnect, # RM-766, be installed on the positive...
    view full answer...
  • Recommended Battery Disconnect For 2015 Ford Edge Titanium
    I confirmed with Roadmaster that # RM-766 is the correct part to disconnect the battery on your 2015 Ford Edge Titanium and I do recommend this part for an easy way to protect your vehicle without needing to move wires each time. This disconnect makes it as easy as a flip of the switch on your dash to make your vehicle drivable or towable. I've attached an installation video of this product for your convenience.
    view full answer...
  • Battery Charge Wire Recommendation for 2014 Jeep Wrangler When Flat Towing
    For the most part yes. A charge wire from your tow vehicle to your towed vehicle will help prevent battery drain as you are on the highway. For that we have the part # RM-766 which is designed to charge the battery and automatically disconnect it when flat towing.
    view full answer...
  • Will Battery Disconnect RM-765 Work On 2014 Smart Car?
    Based on my research, it is required that you disconnect your battery during towing. The Automatic Battery Disconnect For Towed Vehicles, Item # RM-766, is what you need. Consult your owner's manual to confirm what you need to do for your Smart car. If you need anything else to flat tow your Smart car then let me know. Links to additional information attached.
    view full answer...
  • Best Place to Mount Automatic Battery Disconnect from RoadMaster Part RM-766
    The most common place that they are mounted is on the fender or on the firewall, depending on battery location. The heavy gauge wire leads for the battery are long enough to allow flexibility as far as mounting location. It is not an extremely complex operation, and the simpler the operation, the less problems. We have not heard of any problems with the units we sold so far.
    view full answer...
  • Disconnecting the Battery of 2016 Ford Edge For Towing Behind RV
    I'd recommend using a Roadmaster Automatic Battery Disconnect, part # RM-766. The disconnect would allow you to 'disconnect' the battery with a flip of a switch. When the battery is disconnected, the taillight circuit from the RV will maintain the battery in the towed vehicle (you'll need to leave the running lights in the RV on for this to happen). The owner's manual specifically states that the battery needs to be disconnected, I wouldn't recommend doing anything else other than physically...
    view full answer...
  • Is Brake Lite Relay Needed When Flat Towing Vehicle with Battery Disconnect
    If you disconnect the battery of your vehicle with the disconnect kit part # RM-766 you actually wouldn't need a brake lite relay. Reason being that when the battery is disconnected the vehicle wouldn't be able to power the stoplights.
    view full answer...
  • Recommended Battery Disconnect Switch for Two 6V Batteries Connected in Series
    It sounds like you are needing a battery disconnect like the Roadmaster Automatic Battery Disconnect with Switch # RM-766. This kit will allow you to disconnect the batteries with just a flip of a switch. I have attached the complete installation instructions that you can take a look at, along with an image that shows how the unit will be connected to the battery.
    view full answer...
    Image 1 for
  • Do Fuses Need To Be Pulled To Flat-Tow a 2018 Chevrolet Silverado 1500
    There are not any fuses on your 2018 Chevrolet Silverado 1500 that must be pulled before being flat-towed according to the owner's manual. However, you will need to disconnect the battery each time in order to prevent it from draining while in tow and in order to do this with the flick of a switch you can use the Roadmaster Automatic Battery Disconnect with Switch part # RM-766. If you need any other parts to complete your flat-towing setup then please just let me know.
    view full answer...
  • What Would Happen if Roadmaster Disconnect RM-766 Was Switched to Drive Mode When Towing
    If you switched the Roadmaster Automatic Battery Disconnect # RM-766 to drive mode you'd basically be reconnecting the battery of the vehicle. The battery was disconnected to allow the key of the vehicle to be left in the on position so that the wheel would be unlocked and prevent the battery from draining. Long story short you'd drain the battery of the vehicle but no damage would occur beyond that. I attached an install video for this kit on a similar Focus as yours for you to check out too.
    view full answer...
  • Recommended Automatic Battery Disconnect for Flat Towing Saturn Outlook
    For your Saturn Outlook, the Roadmaster Automatic Battery Disconnect with Switch for Towed Vehicle w/ Supplemental Braking System # RM-766 can be installed to allow you to simply flip a switch in your vehicle to go from drive to towing so you don't need to disconnect the battery each time you tow and then reconnect it. I can only assume there was a typo in your question because Saturn only made the Outlook from 2007 to 2010.
    view full answer...
  • Will Roadmaster Battery Disconnect Fit 2019 GMC Sierra
    It looks like the fuse block installs directly on top of the battery for your 2019 GMC Sierra but there still should be a terminal that the positive post of the battery connects to whether it is directly to the positive post or a different location in the fuse block. I reached out to my contact at Roadmaster who confirmed that the Automatic Battery Disconnect # RM-766 will fit and suggested that you have your mechanics inspect the fuse block for a place where there is a terminal.
    view full answer...
  • How To Install the Roadmaster Automatic Battery Disconnect On A 2019 Chevy Silverado 1500
    The process to install the Roadmaster Automatic Battery Disconnect part # RM-766 on your 2019 Chevrolet Silverado 1500 is a bit different than most like the ones you were referring to on our site however it can still be done. I have attached for you a few photos on this process that gives you a few options. Please let me know if you have any questions.
    view full answer...
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