My question is, why we have to pay $2.00 extra of what the sign shows?, I have taken my truck before and is the first time they ask me to pay $2.00 dlls. Extra suppose because is a truck, they should show on the sign.

Then change your sign, that information must also be in view of the client. Let's avoid misunderstandings. Then change your sign, that information should also be in view of the client, avoid misunderstandings

It's the size of your vehicle.

In the employee's view... Your vehicle is large (such as truck, van, etc), so they will charge $2 more to you because they will work on your vehicle at extra time and consume extra water, soap, seal, etc. If you have issues, why not talk with employee or manager.

It is on the sign

Every car wash I been to charges me extra for having a truck. When I take my regular car, it's regular price

I agree. I would call management and complain if I were you.