Before you can back up a trailer, you have to hook it up, and that's where safety starts. A trailer that comes loose on the road is one of the most dangerous things that can happen while towing. Almost every one of those incidents comes down to a step that was skipped or done in a hurry: a coupler that wasn't latched, chains that weren't attached, or lights that weren't checked.
This article walks through hitching a typical bumper-pull trailer, with a ball hitch on the tow vehicle and a coupler on the trailer tongue, and finishes with a quick pre-trip checklist. Always follow the instructions for your own hitch, coupler and trailer, since equipment varies.
Know your equipment
A standard trailer connection has a few main parts:
- Receiver: the square tube mounted under the back of the tow vehicle.
- Ball mount: the removable bar that slides into the receiver and holds the hitch ball. It's held in with a pin and clip.
- Hitch ball: the ball the trailer sits on. It comes in several sizes, commonly 1-7/8, 2 and 2-5/16 inches. The ball size must match the trailer's coupler.
- Coupler: the socket at the front of the trailer tongue that fits over the ball and latches.
- Safety chains: two chains from the trailer tongue to the tow vehicle, a backup in case the coupler comes off.
- Wiring connector: the plug that powers the trailer's lights, and its brakes if it has electric brakes.
- Tongue jack: the crank or jack that raises and lowers the front of the trailer.
Every part has a weight rating, and the whole connection is only as strong as its weakest piece. Check that the receiver, ball mount, ball, coupler and chains are all rated for at least the weight of your loaded trailer. See Trailer Weight and Tongue Weight for more.
Step by step
1. Check the ball and coupler match
Make sure the ball size matches the size stamped on the coupler. A ball that's too small can let the coupler pop off over a bump, even if it seems to latch.
2. Raise the coupler
Use the tongue jack to raise the coupler a little higher than the top of the hitch ball. Open the coupler latch.
3. Back the tow vehicle up to the trailer
Back up slowly until the hitch ball is directly under the coupler. A helper standing to the side, a backup camera, or a hitch alignment guide all make this easier. Stop with the ball centered under the coupler, shift into park and set the parking brake.
4. Lower the coupler onto the ball
Crank the jack down until the coupler sits fully on the ball and the weight of the tongue starts to rest on the tow vehicle. The coupler should seat all the way down around the ball.
5. Latch and lock the coupler
Close the coupler latch and insert the safety pin or lock through it. Most couplers can't be locked properly unless they're seated correctly, but don't rely on that. Test it: crank the jack down a little more and watch whether the back of the tow vehicle drops as it takes the weight. Some drivers also try to lift the tongue slightly with the jack to make sure the coupler doesn't come off the ball.
6. Raise the jack all the way
Crank the tongue jack fully up, and swivel or stow the foot if it's designed to. A jack left partly down can hit the road on the first dip or driveway.
7. Attach the safety chains, crossed
Attach both safety chains to the tow vehicle's hitch, crossing them under the trailer tongue in an X. If the coupler ever comes off the ball, the crossed chains form a cradle that catches the tongue and keeps it from digging into the road. Leave enough slack for tight turns, but not so much that the chains drag on the ground.
8. Connect the breakaway cable
If your trailer has electric brakes, it will have a breakaway cable and switch. Attach the cable to the tow vehicle separately from the safety chains, not to the chains themselves. If the trailer completely separates from the vehicle, the cable pulls a pin that applies the trailer brakes. Many places require a breakaway system on trailers above a certain weight.
9. Plug in the wiring and test the lights
Plug in the trailer wiring and check every light, ideally with a helper standing behind the trailer: running lights, brake lights, and both turn signals. A trailer whose brake lights don't work can't warn the driver behind you that you're stopping.
10. Remove wheel chocks and do a walk-around
If the trailer was chocked, remove the chocks. Then walk all the way around the rig one last time.
The pre-trip walk-around
Before every trip, and after every stop, it's worth a quick check:
- Coupler latched and pinned, sitting fully on the ball.
- Safety chains crossed and attached; breakaway cable attached.
- Wiring plugged in and not dragging; all lights working.
- Tongue jack fully raised.
- Tires inflated to the pressure on the trailer's tire sidewall or placard, and no obvious damage.
- Lug nuts tight, especially on a new or recently serviced trailer.
- Load secured and balanced, with doors, ramps and gates closed and latched.
- Mirrors adjusted so you can see along both sides of the trailer.
On a long drive, stop after the first few miles to check everything again, then at every fuel stop. Feel the trailer wheel hubs: if one is much hotter than the others, the wheel bearing may need attention.
Unhitching
Unhitching is the same process in reverse, on level ground:
- Park, set the tow vehicle's parking brake, and chock the trailer's wheels so it can't roll.
- Unplug the wiring and detach the breakaway cable and safety chains.
- Lower the tongue jack until it's on the ground. Use a block or pad under it on soft ground.
- Remove the pin and open the coupler latch.
- Crank the jack up until the coupler lifts clear of the ball, then pull the tow vehicle forward.
Always chock the trailer before you unhitch. An unhitched trailer on even a slight slope can roll away surprisingly fast.
Practicing in The Trailer Parker
Most lots start you already hitched, with the engine off. Like a real rig, you start the engine in Neutral, let it idle, and only shift into Forward or Reverse while stopped. Choose the Light, Medium or Heavy trailer to match what you tow. A heavier trailer takes longer to speed up and slow down, which is a good reminder of why everything in the connection needs to be rated for the load.
You can also practice the hardest part of hitching: lining the ball up under the coupler. Stop, press Unhitch (or U), pull the truck a few feet away, then back up to the trailer again. The overhead view shows exactly how far the ball is from the coupler, front to back and side to side, and in the 3D view the backup camera becomes a tailgate hitch camera, like the one on many pickups. Get the ball within six inches, stop, and press Hitch. Bump the trailer and it costs points, just as it would cost you a dented tailgate.
For the full job, pick the Hitch Up & Park lot. It starts with the trailer parked on its own and the truck across the lot. You drive past the trailer, back up to the coupler and hitch, then tow it over and back it into a bay. The hitch scores too, up to 20 points if you do it in two or fewer direction changes.