I had a small auto meter shift light in my previous '90 ZR-1. When I sold it I removed it and it has been sitting in a box for years. I just came across it and would love to wire it my (new to me) '90 ZR-1. The problem is I absolutely cannot remember how I did it. I believe one of my friends helped me do it originally.

Just being upfront, I am a complete electric wiring buffoon, lol. There are 3 wires coming out of the auto meter box.... black, red, and green. Where is the best place to tap into for ground, power, and RPM's?

Thanks in advance and I'm sure I'll have more questions.

Jay

 

Contact autometer, if it is one of the older now discontinued pro shift light (psl), or the new digital pro shift light (dpsl) they can help you. Try taking a photo of it, and comparing with images online of autometer shift lights, inspect it for any markings or model number information. Or if you remember where you purchased it maybe contact that vendor for help. There are a few generations of autometer shift lights, so without giving us more info that's about all anyone can suggest.

having said all that, typically red is to switched 12 volt +, black to ground, and green to the coil, or ignition box. In the zr1 it's difficult to say where you'd wire the green lead to. Best thing to do in your case is probably just purchase a new shift light. Holley sniper and other shift lights are cheap, easy to program and setup. I'd hate to see you hurt your hard to find lt5 ignition box trying to use a 20 year old light. When you can purchase a new stand alone light for $150 or less. Now days you can pick up the old msd rpm activated switches used cheap, then simply wire it's output to just about any 12 volt bulb or the cheaper shift lights that are not built with an rpm switch in them. But either way, a new light would be $100-$150.

 

Very true... good point. Thanks for the suggestion

 

If you were really industrious (and your ZR1 is similar to my base 89), there's a shift light in the dash (ZF6). I can program (via chip) when it comes on. Otherwise, it's already programmed where you're supposed to shift. I'm thinking you could "piggyback" off that light -- to make a bigger, external one. Or maybe you haven't even noticed that light? It's small.

In my case (with a piggy-back chip), I can designate turn-on for each of the ZF6 gears.....Or...just turn it off. Like I did. I can't remember for sure (since it's been 12yrs)....It might be an arrow that points up? Or...it might have said "Up Shift"?

 

As far as I know, I've never seen any stock form of shift light in the ZR-1's. I'll have to look into the timing test connector near the brake booster. This is probably the best way to go.

 

Hmmm...I was suprised, so I searched. Ironically, it's there -- but disabled.
https://www.corvetteforum.com/forums...ift-light.html

 

I wired the "shift" light in my 91 MN6 base coupe dash to trigger at 5800, then wired the 1-4 skip shift light to come on in sequence at 6000 off the Holley HP it's just enough to get your attention, except for facing directly Into the sun early in the morning when the sun is low. It works ok.

 

Does the zr1 zf s6-40 have a sensor on the shifter to tell the ECU what gear it's in? I was unaware of any difference between the base l98 and zr1 zf except for the difference in input shaft length. The cags just activates a solenoid and blocks 2nd and third gear when active, so it forces you to go to 4th under certain throttle and rpm conditions. I can see how what you describe could be rpm based. But how is the ECU sensing what gear it is in? I know the Holley HP transmission icf can be setup to sense an rpm drop to indicate a gear change, but that's only for a drag race scenario. It doesn't actually know what gear it's in unless you have some sensors and elaborate wiring. but it seems unlikely that the 89-95 zr1 ecu had that capability? How exactly does it "designate turn-on for each of the ZF6 gears" when the transmission doesn't have anything to indicate what gear it's in (aside from the reverse light switch and cags circuitry). I am genuinely curious how you are doing that, does the zr1 ecu have some additional lines of code to indicate gear? Seems like it would just be a rpm based shift light. You have me wanting to investigate the 91 fsm I have to see if the wiring for the zr1 has any such circuits.

 

So it does have additional lines of code to make the light output active under different scenarios, that makes sense. By knowing engine rpm, and wheel speed along with transmission gear ratios it can be told to shift at x rpm in this gear, or y rpm in that gear.. I still find that interesting, the 91 I have did route the vss through the ECU, then condition it's signal and send it on to the ccm to go to the lcd speedometer. I keep forgetting the lt1 and zr1 had early forms of traction control via the esr, or vsr? As well as ride control that would make shock adjustments based on road speed and other things. Makes sense when you consider the zr1 was a $35,000 upcharge. Would be cool to be able to program a shift light to different rpm in different gears. Neat stuff! Thanks for responding brother, I appreciate it. I learned something today. Pretty awesome just how advanced these cars were for the era. If gm had just used the lt5 ecu and sequential injection in the l98/lt1 cars for 89-90-91 I'd have kept the factory ECU instead of buying the Holley HP. The only feature I lost is cags, and economy, fuel range display.

 

It is surprising what their "logic" contained back then. For those who might be curious, here are the parms used to determine "shift light activity"...in my 89 base MN6 car.

 

That's pretty cool, had no idea.

 

To be clear, JTZRWon, I should have posted the shift-light feature may be disabled. I don't have a ZR1, nor is it clear in that thread. I would be surprised they put the bulb and the wiring in the dash -- without actually USING IT!!! But hey....weirder things have been noted in the C4 platform.

Another example would be a feature to lean fuel mixture -- and save gas. It's also there (in mine) but was disabled by virtue of a parm "out-of-range". I activated it -- by putting a valid value in the appropriate cell. I never compared before/after to see if it's actually working. I wasn't terribly brave about it either -- as the user can specify HOW LEAN you want to get. I just leaned it a hair....maybe not even a half-a-point. It's a hwy thing too. I have to be driving above 60mph under very light load -- to trigger SLIGHTLY leaner mixture.

The best way to prove it would be an out-of-town trip with and w/o the feature activated. Even then, weather/wind conditions might alter the results? I have to think GM didn't want to add ANY feature that might increase warranty engine claims....especially if it's inclusion wouldn't significantly lower the entire EPA fleet ratings. AFAIK, this is the overall goal of carmakers.