How to Hook Up a Trailer

This guide will outline the proper way to connect a trailer to a vehicle

Prior to hooking up to a trailer, take the following steps to make sure you have the proper vehicle and equipment to tow a trailer:

        • Towing Capacity & Load Capacity – Check your towing capacity of the towing vehicle to ensure that your vehicle is capable of pulling the trailer plus the weight that you will load on the trailer.  Check the trailer capacity to ensure that you are not going to exceed the manufacture and DOT weight limits.  In California, a trailer with 10,000 GVWR or more requires a commercial driver license (CDL).  GVWR is the total weight of the trailer and its load.
        • Brake Controller – Make sure you have an electric brake controller.  Without a brake controller, you will not have trailer brakes.  This is usually a small module under or on your dash.  Some are OEM and others are installed aftermarket.  If you don’t have one, they are fairly inexpensive and easy to install, but it should be installed by a professional.
          • Tow Package – Make sure that you have a tow package.  A ball mounted to the bumper will not provide enough support to safely tow a trailer.  A tow package is an under mount bracket designed to support the trailer and load you will be hauling.  A class IV tow package is recommended.
          • Light Plug – Check the light plug receptor on your towing vehicle to make sure it is the same plug as the trailer.  The two common plugs will be 4 pin and 7 pin.  Most larger trailers, and all trailers rented by Big Trailer Rentals will be the 7 pin plug.  You can identify the 7 pin plug as a round plug with 6 outer pins and 1 center pin.

      Follow these steps when hooking up a trailer:

            1. Ball Size – Make sure that you are using the right size ball.  The common sizes are 2″ and 2 5/16″.   The ball size will be written on the top of the ball.  Check the ball to make sure it has some grease on it.  If it is dry or rusty, you should apply a little grease on it.  Curt Manufacturing makes high quality commercial duty forged ball mounts and there are a couple others on the market as well.  These can be purchased on Amazon or at Tractor Supply.
            2. Trailer Height – Adjust the height of the trailer to the approximate height of the ball on your towing vehicle using the trailer jack.  The trailer should look level from front to back.  It may be necessary to adjust the ball height of your towing vehicle to make the trailer level.
            3. Backup to Trailer – Use a spotter or a backup camera to back up to the trailer and align the ball under the coupler of the trailer.
            4. Connect Trailer – Using the trailer jack, lower the trailer coupler onto the ball of your towing vehicle.  Make sure the jack is all the way up.
            5. Coupler Latch – Move the coupler latch to the locked position.
            6. Hitch Pin – Place the hitch pin into the coupler latch pin hole or hitch pin hole.  This will secure the coupler lock so trailer does not come disconnected from the ball.
            7. Safety Chains – Hook both safety chains to the safety chain hooks of the towing vehicle.  Safety chains should always be crossed in accordance with DOT standards.
            8. Breakaway Cable – Connect the trailer breakaway cable to the towing vehicle.  In most cases, this will connect to the safety chain hook.  This should never be connected to the safety chain in order to be in compliance with DOT standards.  It’s recommended to use a red spiral Fastway ZIP 6′ breakaway cable.  This will prevent your breakaway cable from dragging on the ground fraying which is what commonly happens with the standard breakaway cable provided by the trailer manufacture.
            9. Trailer Plug – Connect the light plug to the towing vehicle.  Connecting this plug will provide trailer lights and trailer brakes with use of a brake controller.  You should always check for debris or corrosion in the trailer plug and the plug receptor.  Debris or corrosion can prevent lights and / or brakes from operating properly. An air hose or can of air can usually remove and debris.  At Big Trailer Rentals, we use QD Electronic Cleaner to remove any corrosion and keep the connections clean.  After you connect the trailer plug to the vehicle, run the plug cord through the hitch pin and leave approximately 9″ of slack between the hitch pin and the plug receptor on the towing vehicle.  This will allow slack for turns and prevent the plug cord from dragging on the ground.
            10. Review – Double check steps 1-9 to ensure everything is properly attached and secured.  It only takes an extra minute to enure safety.
            11. Light Check – Perform a light check to ensure turn signals, hazard lights, running lights, and brake lights are working.
            12. Trailer Inspection aka Pre-Trip Inspection – Perform a thorough trailer inspection to ensure tires are properly inflated and in good condition.  Make sure the trailer deck is clear of debris and ramps are secure.  If loaded, ensure that load is properly secured.
            13. Brake Controller – A typical brake controller will have an adjustment of 1-10.  When empty, set your brake controller to 1 or 2 for initial testing of the braking ability, depending on the size and weight of the trailer.  When loaded, set your brake controller to higher number than the number that provided adequate braking power while empty.  This number will depend on the weight of the load as well as the type of brake controller you have.  In most cases, you won’t need to set your brake controller as high as 8-10, but again, this will be different for every situation.
            14. Brake Test – Before traveling on a busy highway or road, test the brakes.  This test should always be done on gravel to avoid causing any damage to the tires.  On a gravel driveway or road where there is no traffic, drive 5-10 MPH and press on your brake to test your stopping ability.  Adjust your brake controller setting up or down as necessary.  There is a fine balance between having enough braking power to stop but not so much that you skid.  If your trailer tires are locking up and skid on pavement, you will put flat spots on the tires and they will need to be replaced.  This is a costly mistake made by many.  It’s always a good idea to take a quick glance at the trailer tires in your mirror while braking to watch for smoking tires.  If you see smoke while braking, your brake controller is most likely set too high.  In some circumstances, brake adjustment settings may also need to be evaluated by a mechanic.
            15. Driver Safety – Make wide turns, check your mirrors, and always remember to get out and look before backing or have a spotter guide you as you back.

      At Big Trailer Rentals, we have staff to hook up a trailer for you or assist you in the hook up process to ensure that you have an excellent trailer rental experience.  However, the driver is responsible with all safety aspects of towing a trailer.

      Prior to loading a trailer, check out our guide: How to Load a Trailer

      If you have questions about towing a trailer or renting a trailer, call Big Trailer Rentals at 951-514-6980.


      Disclaimer: The information contained on this page is provided by Big Trailer Rentals, LLC as a general guide to assist with towing a trailer and is not endorsed by DOT.  Each trailer and situation is different and some safety information may be omitted from this guide.  It is recommended that you check your own resources and federal and local laws pertaining to safety regulations while towing a trailer.  Big Trailer Rentals, LLC is in no way liable for use or implementation of information provided in this guide.