This is not the best plan as your car will probably smell. But sometimes you have to dry your wetsuit in the car when you are going somewhere and you cant leave your wetsuit hanged outside over the fence or something. So you’ll lock it in your car. The problem here is ventilation, without wind and fresh air air in the car will soon become saturated with moisture and the wetsuit will stop drying. So you should leave your car windows opened at least a little bit. Next thing is where to put it? If you have a car that is high enough to hand your wetsuit in it then this is the best way. Put the bottom of your wetsuit in a plastic box and hang the top somewhere in your car. And let the gravity do its work and drain some water from the wetsuit. Actually this is a smart thing to do even if you have a small car. If you can not hang it then there is not much you can do. Just don’t leave it in a plastic bag :).
If you will be driving for a while this also works really well:
- cover your passengers seat with some plastic bags, boardbag or poncho
- throw the wetsuit over the seat so it is spread out nicely
- undress down to your t-shirt and crank up the heating
- max warmth and max ventilation
- direct the vents into the wetsuit
- drive around
In a 2-3 hours of this your wetsuit will be almost completely dry.

Even better can your wetsuit be dried if you own a camper van that has a bathroom and heating. Camper van bathrooms usually have their own heating vent. Because they are tiny, just a little bigger closest it get really really hot inside if the heating is cranked up.
If you put wet wetsuits into the bathroom and turn on the heating during the night your wetsuit will be completely dry in the morning. If you could design a custom wetsuit drier room camper van bathroom would be it!
By the way, if you are thinking of getting a camper van, I recommend this camper van guide for beginners, it will tell you everything you need to know about camper vans and camper van traveling.