Shift up light not functioning properly
03-12-2014, 09:41 AM
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Shift up light not functioning properly
Hello all I am new to the forums so I am not sure if this is in the proper section, but I will gladly move this to the proper section if need be. On to my problem. I have a nearly original 1991 camaro rs with the 5.0 tbi coupled to a t5 world class transmission. Just yesterday I converted my instrument panel to blue led illumination, which looks and functions well. While I had the panel out, I noticed that the shift light bulb was missing. Since I had a few extra bulbs, I plugged one into it. Now when I run the car, the shift light only comes on in 4th or 5th when there is a light load on the engine, or when I am at highway speeds. What do I need to do to make the shift up light function as it should? As I mentioned before, the car is an original manual car, although the instrument panel was replaced by the previous owner due to an inop speedometer, which I suspect was taken from an automatic car. Thanks in advance!
03-16-2014, 04:40 PM
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Car: 85 IROC / 69 Firebird convertible
Engine: 5.0 / 350
Transmission: t-5 / WC t-5
Axle/Gears: 3.27 / 3.08
Re: Shift up light not functioning properly
The bulb was probably out for a reason, THAT reason. No problem, I don't think you need a light on the dash to tell you when to shift anyway. Just pull the bulb back out and go back to the way it was.
I didn't realize any third gens even had up-shift lights. Last one I remember seeing was in an '85 Sunbird. Does it not have a tach?
I didn't realize any third gens even had up-shift lights. Last one I remember seeing was in an '85 Sunbird. Does it not have a tach?
03-16-2014, 04:51 PM
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Car: 4/89 IROC Z28 G92 -
Engine: LB9 TPI
Transmission: T-5
Axle/Gears: 3.45
Re: Shift up light not functioning properly
My 89 5 speed has one too..... it's for fuel economy I think was the idea behind it. While I just ignore mine... if it didn't work, I don't think I'd fix it.
Actually I was thinking it would be cool if the worked for high rpms...at red or yellow line.
Actually I was thinking it would be cool if the worked for high rpms...at red or yellow line.
03-17-2014, 06:12 AM
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Re: Shift up light not functioning properly
Yeah, I have a tach. I can shift on engine sound alone due to years of driving old honda atvs, but my buddy I occasionally let drive my car thinks my car has a 4 banger and shifts as such, (like cruising at 3k rpm in 4th gear). 
Does it show you when to shift for best fuel economy? I was hoping it showed the best powerband.
Does it show you when to shift for best fuel economy? I was hoping it showed the best powerband.
03-17-2014, 05:16 PM
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Car: LOWERED ♦ CRIMSON METALFLAKE
Engine: ► 400 KUBES ◄
Transmission: 765R4
Axle/Gears: EATON POSI 4.56
Shiftless In Seattle
The shift light gets it signal from a PROM VIA the ECM.
The shift light is affected by the Coolant Temperature Sensor, the Throttle Position Sensor, and of course RPM.
So you can check those sensors to make sure they are still in spec.
You can have the PROM checked by someone with the equipment for that.
You stated the speedo was replaced.
Make sure the VSS route was not altered by the PO.
The shift light is not supposed to illuminate in 5th therefore is consistent with at least 1 parameter being way off.
A non-stock differential gear, unusual transmission ratios verses what is supposed to be for your VIN can also cause the shift light to malfunction.
The shift light in your car is not similar to a shift light in a drag car.
It is not programmed to shift at a certain RPM alone.
That’s why you will see it come on, even when operating properly, at times that don’t seem to make sense.
◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙
Happy Racing !
◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙
Don’t Blame Me For Spinning Him, My Car Simply Took The Air Off His Spoiler
The shift light is affected by the Coolant Temperature Sensor, the Throttle Position Sensor, and of course RPM.
So you can check those sensors to make sure they are still in spec.
You can have the PROM checked by someone with the equipment for that.
You stated the speedo was replaced.
Make sure the VSS route was not altered by the PO.
The shift light is not supposed to illuminate in 5th therefore is consistent with at least 1 parameter being way off.
A non-stock differential gear, unusual transmission ratios verses what is supposed to be for your VIN can also cause the shift light to malfunction.
The shift light in your car is not similar to a shift light in a drag car.
It is not programmed to shift at a certain RPM alone.
That’s why you will see it come on, even when operating properly, at times that don’t seem to make sense.
◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙
Happy Racing !
◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙
Don’t Blame Me For Spinning Him, My Car Simply Took The Air Off His Spoiler
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