motor's in cars are always connected to a hot sorce , via switch or relay, and the other wirer is connected to the body ground. So considering this, I would have to say parrell.
They are wired in parallel, series and series - parallel.
A parallel circuit
2 batteries are wired in series then these 2 are wired in parallel with the other 2 which should also be wired in series. series is positive to negative and or negative to positive. parallel is pos. to pos. and neg. to neg.
it would be kind of both
House lights are wired in parallel. If they were in series, when one burned out, all would. Christmas lights are wired in a combination of series and parallel - roughly 50 lights in each series string. that's why if one bulb burns out, a section of the lights goes out.
You get more voltage and current capacity.