I've used the Johnson a419 for years for many more applications than you could possibly think of- an absolute staple on the truck. From water heaters to defrost- even light timers. I carry the 240/120v and a 24v and almost always can get me out of a jam.
Compact and versatile- works in a wide range of temperature and humid environments. Can be a pain to mount, can be a pain to wire, can be a pain to program, but is reliable and accurate.