We elected to mount the two Gear Vendors indicator lights on our Stewart Warner gauge panel. The red light (left) is the Autostart indicator. When the overdrive button is engaged from a stop or a very slow roll, this light will come on. It lets you know that overdrive will automatically engage once you exceed approximately 15-20 mph (the in-shift threshold). The green light is the overdrive indicator, and tells you that the overdrive is now engaged. Overdrive automatically disengages (the out-shift threshold) when vehicle speed dips below 5 mph.