Winter is coming. If you are in a worktruck, in a car with a broken heater. There are 12 volt heaters that will make driving more comfortable for you. The more powerful units will require hooking up to the battery with power wire, less powerful units will work off the cigarette lighter plug in your car. 12 volt.
Below are some ceramic heaters which are probably the best and most powerful
The comfort zone heater is a good looking heater with a ton of positive reviews
Another option is to add a heated seat, so it can warm you from the bottom up. Here is a good car seat heater with positive reviews: