Hooking up a trailer looks simple, and most of the time it is. But nearly every trailer that comes loose on the highway traces back to a step someone skipped in the driveway: a latch that never closed, a pin left out, chains hanging loose or lights that were never checked. The fix is to do the same steps in the same order every time.
Here is how to hook up a trailer to your vehicle, step by step, with a checklist you can keep in the truck.
Before You Back Up: Match the Parts
Check these before the trailer ever touches your hitch:
- Ball size: the size is stamped on top of the coupler, commonly 1-7/8, 2 or 2-5/16 inches. Your hitch ball must match exactly. A ball that is even slightly small can pop out of the coupler on a bump.
- Ratings: the ball, ball mount and hitch are each rated for weight. The lowest rating is your limit.
- Height: the trailer should sit close to level when hitched. A drop or rise ball mount fixes a mismatch between your hitch height and the coupler.
- Connector: your vehicle's plug has to match the trailer's, usually a 4-pin flat or a 7-way round. An adapter can bridge the two.
How to Hook Up a Trailer, Step by Step
- Chock the trailer wheels. Put chocks in front of and behind a tire so the trailer cannot roll while you work.
- Open the coupler latch. Lift the latch or release lever so the coupler is ready to drop over the ball.
- Raise the tongue. Crank the tongue jack until the coupler sits a little higher than the top of the ball.
- Back up slowly. Line the ball up under the coupler. A helper standing where you can see them in the mirror makes this much easier. Agree on hand signals first. Our Towing 101 Chapter 9 on hooking up covers backing up with and without a spotter.
- Lower the coupler onto the ball. Crank the jack down until the coupler seats fully on the ball and starts to lift the rear of your vehicle slightly.
- Close and lock the latch. Push the latch down until it locks, then insert a pin or coupler lock through the latch.
- Do the lift test. Crank the jack up a few turns. If the coupler stays on the ball and the vehicle rises with it, you are coupled. If the coupler lifts off, it was never latched. Start over.
- Raise and stow the jack. Crank it all the way up, and if it swivels, rotate it to its travel position and lock it.
- Check the hitch pin. Confirm the pin holding the ball mount in your receiver is in place with its clip.
- Cross the safety chains. Run the chains in an X under the coupler and hook them to your hitch's chain loops. The crossed chains form a cradle that can catch the tongue if the coupler ever separates. Leave enough slack to turn, but not so much that they drag.
- Attach the breakaway cable. If the trailer has electric brakes, clip the breakaway cable to the vehicle, not to the safety chains. If the trailer separates, the cable pulls a pin and applies the trailer brakes.
- Plug in the lights. Connect the plug and route the cord so it will not drag on the road or pull tight in a turn.
- Test every light. With a helper, check running lights, brake lights, both turn signals and hazards.
- Test the brakes. Roll forward slowly and apply the trailer brakes with your controller's manual lever. Our guide to brake controls covers controller settings.
- Remove the chocks and do a walk-around. Check tire pressure, doors, ramps and the load.
The Trailer Hookup Checklist
Save this list on your phone or tape it inside the glovebox:
- Ball size matches the coupler
- Coupler fully seated, latch closed, pin or lock in place
- Lift test passed
- Jack raised and stowed
- Hitch pin and clip in place
- Safety chains crossed and hooked
- Breakaway cable attached to the vehicle
- Wiring plugged in, not dragging
- All lights working
- Trailer brakes respond
- Tires inflated, lug nuts tight
- Doors, ramps and gates closed and latched
- Load balanced and strapped down
- Mirrors adjusted
Why the Brakes and Breakaway Matter in Georgia
Georgia law requires brakes on all wheels of a trailer with a gross weight of 3,000 lb or more, counting the trailer and its load. For vehicles in business use over 10,001 lb GVWR, the Georgia Department of Public Safety lists a breakaway braking system among the required brakes. Checking your breakaway cable each time you hook up keeps that system ready to work.
Common Hookup Mistakes
- Latching on top of the ball. The coupler can look seated when it is resting on top of the ball. The lift test catches this.
- Uncrossed or dragging chains. Straight chains cannot cradle the tongue, and dragging chains wear through.
- Breakaway cable clipped to the chains. If the chains hold, the cable never pulls. Clip it to the vehicle.
- Skipping the light check. A burned-out bulb or loose ground is easy to fix at home and expensive to find out about from a trooper.
- Jack left down. A jack foot that catches a speed bump can bend the jack or the tongue.
How to Unhook a Trailer
Unhooking is the same list in reverse. Park on level ground, chock the wheels, unplug the wiring, unhook the breakaway cable and chains, lower the jack to take weight off the ball, open the latch and crank the coupler up off the ball before you pull away.
Need Parts Before You Tow?
If your coupler latch is worn, your chains are short or your plug does not match, our trailer parts counter in Jonesboro stocks couplers, wiring harnesses, adapters, brake controllers, locks and tie-downs, and most parts are ready the same day or the next.
Come see us at 8834 Tara Blvd, Jonesboro, GA 30236, just south of Atlanta. We are open Monday to Friday 9 AM to 5 PM and Saturday 9 AM to 4 PM. Call (770) 603-8511 or text (404) 383-8194 and tell us what you need to haul.
Frequently Asked Questions
How do you hook up a trailer to a truck?
Chock the trailer, open the coupler latch, raise the tongue, back the ball under the coupler, lower it onto the ball, latch and pin it, raise the jack, cross the safety chains, attach the breakaway cable, plug in the lights and test the lights and brakes.
How do I know the trailer is coupled correctly?
Close and pin the latch, then crank the tongue jack up a few turns. If the rear of your vehicle rises with the trailer, the coupler is locked on the ball. If the coupler lifts off, it was not latched.
Why do you cross safety chains under the trailer tongue?
Crossed chains form a cradle that can catch the trailer tongue if the coupler separates from the ball, keeping it from digging into the road.
Where does the breakaway cable go?
Clip it to the tow vehicle, not to the safety chains. If the trailer separates, the cable pulls a pin that applies the trailer's brakes.
What size ball do I need for my trailer?
The ball size is stamped on top of the coupler, commonly 1-7/8, 2 or 2-5/16 inches. Your ball must match it exactly.