You need to contact U-Haul, either use their website or talk to a dealer. There are 2 types of car haulers: the tow dolly in which only the front wheels are off the ground (and it DOES NOT have a braking system) and the auto transport in which the entire vehicle is off the ground (and it has a surge-brake braking system). Both units use a flat-four connector for activation of the trailer's lights. When you contact U-Haul, they will input information concerning both your tow vehicle (including year, make, model and type of hitch system installed) and the vehicle to be towed, into their system to determine if that combination will work and is allowed. As someone who works at a shop that also is a U-Haul dealer, I HIGHLY RECOMMEND you do this ASAP. We have people who come in "off the street" to rent a dolly or AT (auto transport) right now and we have to turn them down because the U-Haul system will not allow their combination of TV and towed vehicle to be used. Not very "happy campers"; but our hands are tied. You can reserve a unit ahead of time, but be aware that you may have to travel to another dealer if it is not available at your local dealer on the date you need it. U-Haul will contact you 24 hours ahead of time to let you know what the situation is. Also, if you are going one-way, have some info about your destination, if possible, such as address and ZIP code. It helps us a lot to speed your rental. If you are paying cash upfront, expect to also include a refundable deposit. With credit cards a deposit is not required. You also have a choice for insurance and can decline it BUT, I recommend you make sure that your insurance company will cover a rental U-Haul tow vehicle, because if you damage the U-Haul vehicle, they are going to want immediate reimbursement and you are on the hook for the entire amount. Again....contact U-Haul ASAP, don't wait until the day before or the day of, your trip.