94ElBanditoDeCa

I have an 88 Firebird with a 2.8 MPFI 5-speed manual transmission.

So I recently replaced my check engine light bulb and I discovered out of the 8 indicator bulbs my car only uses four. 1) Seat belt 2) brake 3) check engine 4) Last but not least the awesome Shift Up indicator.

I know some people think its a dummy light to have but I think its awesome since its stock. I would love for the light to work so I replaced the bulb since it was burned out too. That didn't work then I thought it was the socket so I switched it with a good one but it still didn't work. Then I thought maybe it will only light up if I drove and shift gears but nope.

I checked in the Chilton hand book for a wiring diagram but there's no bulb or switch layout. I'm stumpped so now I'm here for all y'all help. Please I want to know what it could be.

RedLeader289

iTrader: (2)

I THINK that the shift lights on these cars are tied into the computer somehow, perhaps. Have you traced the wires and checked for fuses?

RJMcEachern

on my 87 GTA 5.7L Auto, I enabled the shift light in the ECU. So I am almost certain yours will be the same.

RJMcEachern

94ElBanditoDeCa

Well I doubt its a fuse because im sure its only one that links the gages. Also I did some digging around in the forums and I found this
https://www.thirdgen.org/forums/showthread.php?t=10727

Its an old post of someone trying to fix the shift light. Someone had suggested that if its not functioning properly it could be the VSS( vehicle speed sensor?).
This confuses me because wouldn't this also mean that my speedometer would be off? Even though it works fine.

drdave88

iTrader: (3)

There are a couple of possibilities, someone may have replaced the ECM at one point w/ an ECM for an auto, which will not have the provisions for the shift light, or your ECM is bad (i wouldnt think this is likely). The circuit board/wiring on the back of the cluster may have gone bad. I personally, hated the thing. It tells you to shift at a very low RPM for emissions regulations to help the car meet EPA standards. I remember before I took the bulb out of mine, i was in 5th gear at 27mph if I went by the bulb. The car wouldn't get out of it's own way. It was extremely annoying. This isn't a shift light like you may be thinking they have in performance vehicles, its not really a cool feature to have.

Scorpner

iTrader: (4)

I have a pick-up from that era where they took out the tach altogether leaving just that stupid light.

sofakingdom

iTrader: (1)

If memory serves, they used the same driver for the TCC in an auto ECM, as the bulb in a stick ECM. I.e. if you put that bulb into an auto car, the light will come on whenever the TCC is commanded to engage.

If it's burned out now, then either (a) it worked at one time, or (b) somebody put a burned-out bulb in it. Knowing what I know about "effort" and "likely" and all that, I'll let you do the math on which one makes more sense.

Dave is right, in cars that have that, it's an emissions/economy thing, programmed to annoy the driver if he doesn't cooperate with Big Brother, kinda like the "skip shift" in the 4th gen T-56. Mostly just an annoying PITA.