Does anyone have any idea what the toggle switch and red and green lights in the dash "might" be for? 1972 GMC 402BB with a 700R4 transmission. Looking at other dash bezels I'm pretty sure these aren't a stock item since they're nowhere to be found on replacement bezels.
When I crank the truck the red light comes on and stays on typically for quite a while, after a while the red light will go off and the green light will come on, pretty much only when I touch the gas (and I mean even lightly touch) and then again, a minute later I might touch the gas and neither light comes on.
I flipped the switch and nothing discernible happened, haven't flipped it going down the road for this unfounded fear that it'll "do something bad" (ahaha god what a chicken).