The altimeter lit up at night. It came with the two bulbs & bulb condoms so I didn't have to find them at the junkyard. It also came with enough wiring to wire it to my heater control light. The brightness/dimness of the gauge syncs with the dimmer switch for the dash. My Runner sits in San Jose, CA where it is 94 feet above sea level. So the altimeter is just above the zero. 20 minutes East of here is Mt. Hamilton, and it's fun to see the gauge climb as I drive up to the Lick Observatory. I carry a couple of Thomas maps where I can tell which mountain/hill I am on by the altimeter and the reading on the Thomas map. To be honest, the tilt gauges are pretty much useless to me unless I am checking fluids and need to be on a level surface.