Electrical connections tend to be the most likely problem, however even those are few and far between. However when your employees have electrical/eltronics training, fixing these problems are easy.
Here is our plan to keep breaks downs from happening. To this day we have never had to pull a truck out of service to fix it. Never a break down, if it snows the truck rolls, does this plan take some time yes.
After a storm, every truck gets washed. Then I take one or two of my electronics guys, and they go over the plow, and any electrical connections that are needed for plowing. These guys are quick, the two of them can check a truck in 8-16 min if they had to. Then again they got about 1K in electrical meters to use. After that the plows are parked, and someone inspects the welds later in the day.
Another thing to do, is set the trucks up early. Now is this is your daily driver it may not be an option. If it is going to snow tuesday night, we put plows on monday. First an operator inspection, and if something seams wrong, and quick electrical insprection. This way if parts are needed, the job isn't rushed. Then the guys can rest up during the day on tuesday.
Geoff