According to the manual, my 84 Rabbit should not have an indicator"idiot" light in the form of an off/on orange arrow. I assumed it was like the idiot light on my Chevy S10 and useless but when I started adjusting the fuel screw on my non turbo engine, as I decreased the fuel (less smoke), the light would start staying off at 55 mph whereas when I got the used car it was pretty much on all the time. Still is on in 3rd except without a load. Is it actually measuring something aside from RPM's? Vacuum?
I know it's a dumb question but....
It's the upshift light. There are probably two switches on top of the IP, operated by the throttle rod. These are what activate the light.
so why is it sensitive to the fuel available from the pump?