Factory shift light modification

So I was driving my new-to-me '96 XJ around the other day when I happened to glance over at my gauge cluster and was like "Why is there an orange house light on?" lol. After I shifted, it went away (for a while anyways) and after about 20 or 30 minutes, I was able to piece together that it was probably an upshift idiot light for the manual transmission. Checked the owner's manual and yep, it's there to tell you when to upshift for best fuel economy. Personally, I think it's pretty cool and handy (might just be because I've never seen one before) but it's kinda hard to see as the steering wheel blocks it most of the time. Today I got to thinking "Well, it's probably just a 12 volt light that's wired into the computer or a switch somehow, how difficult would it be to move it somewhere more visibile?" I was just wondering if anybody had done this before? If so, where'd you put it, how well does it work for you, what'd you use, etc. I'm kinda thinking that disconnecting the wire and running it up to a little housing about the size of an old-school, side-mounted license plate light on top of the steering column with a little amber lense that says "SHIFT" or something would be pretty cool.

The Jeep trans doesnt warrant a shift light, and the light itself's accuracy is a joke...
meh.

I dunno... I have acess to some pretty good diagnostic scan tools through school... I could probably slap on one and look at the different signals and values while driving it around to see how good it's accuracy is. Ya know, for science... My guess is it's running off the MAP sensor signal (higher pressure=less vacuum=less fuel efficient) TPS signal (same thing, more throttle=more pressure), the engine speed signal, or a combination thereof. Mitchell OnDemand and/or Alldata (which I also can access through school) might have a method of operation write-up on it as well.

I went through a very similar reaction when I discovered that light on my '96, at least up to the point of figuring out that the orange house was to tell me to shift. However, at that point my mind immediately revolted against the idea that anybody was going to tell me when to shift.

Everybody's different.

Perhaps if the light came on when I was approaching redline it would be a different matter, but as far as I can tell the parameters upon which it operates all revolve around saving the whales. If I drove according to the shift light I would be getting passed by joggers. I am grateful that my hand on the steering wheel obscures it most of the time.

There are real shift lights available for racers. I believe MSD has them, and those you can set for an RPM value. They are intended to be mounted in a high visibility location. I expect you could figure out how to trigger one off the existing shift light and mount it in a more visible location.

xcm said:

The Jeep trans doesnt warrant a shift light, and the light itself's accuracy is a joke...
meh.

Click to expand...

Especially when tires and gears are changed