How to get to the check engine light - 1987 Firebird
08-27-2021, 07:33 PM
#1
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How to get to the check engine light - 1987 Firebird
Hello all, (Solved)
A couple of years ago I converted my 87 Formula to the Holley Sniper system. Runs fantastic. Since the conversion the check engine light is on because the computer is gone. It bugs me to no end. Does anyone have any ideas on how to get to the bulb to take it out, I do not want to take the dash apart. How would a regular or repair shop get back there to change a burned out bulb?
Thanks,
Louis
A couple of years ago I converted my 87 Formula to the Holley Sniper system. Runs fantastic. Since the conversion the check engine light is on because the computer is gone. It bugs me to no end. Does anyone have any ideas on how to get to the bulb to take it out, I do not want to take the dash apart. How would a regular or repair shop get back there to change a burned out bulb?
Thanks,
Louis
Last edited by Ct1987; 08-28-2021 at 05:51 PM.
08-28-2021, 12:10 AM
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Car: '89 Firebird
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Re: How to get to the check engine light - 1987 Firebird
08-28-2021, 08:00 AM
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Re: How to get to the check engine light - 1987 Firebird
08-28-2021, 08:36 AM
#4
Re: How to get to the check engine light - 1987 Firebird
Iirc you had ccc, might try finding the lamp driver module and remove
https://www.thirdgen.org/forums/dfi-...l#&gid=1&pid=3
https://www.thirdgen.org/forums/dfi-...l#&gid=1&pid=3
08-28-2021, 09:03 AM
#5
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Re: How to get to the check engine light - 1987 Firebird
Iirc you had ccc, might try finding the lamp driver module and remove
https://www.thirdgen.org/forums/dfi-...l#&gid=1&pid=3
https://www.thirdgen.org/forums/dfi-...l#&gid=1&pid=3
Louis
08-28-2021, 09:08 AM
#6
Re: How to get to the check engine light - 1987 Firebird
There is a separate driver module on the ECM in this application. The module does the pull-down for the SES lamp. Basically, it completes the ground circuit for the lamp. The power for the lamp is supplied by the GAGE fuse. The module should be in the auxiliary relay panel on the right (passenger) side of the dash. There should be four wires connected, yellow, pink/black, white/green, and black or black/white.
In addition to a failed (shorted) driver, any grounding of the circuit outside the driver (yellow wire) will keep the lamp on as you describe. If you disconnect the lamp output from the driver module and it stays on, the problem is outside the module. Pin "D" in the ALDL is also connected to the ground side of the lamp and driver module output, so any problems with the wiring there can also cause the lamp to remain on.
Standard Motor Products RY-536
If the module has failed there's a good chance the 1N4001 diode is shorted or the TO-92 NPN transistor has shorted E-C. Both can be had HERE but I'm not sure we can afford the 64¢ each to solve this.
In addition to a failed (shorted) driver, any grounding of the circuit outside the driver (yellow wire) will keep the lamp on as you describe. If you disconnect the lamp output from the driver module and it stays on, the problem is outside the module. Pin "D" in the ALDL is also connected to the ground side of the lamp and driver module output, so any problems with the wiring there can also cause the lamp to remain on.
Standard Motor Products RY-536
If the module has failed there's a good chance the 1N4001 diode is shorted or the TO-92 NPN transistor has shorted E-C. Both can be had HERE but I'm not sure we can afford the 64¢ each to solve this.
08-28-2021, 05:58 PM
#7
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Re: How to get to the check engine light - 1987 Firebird
Looking carefully at the dash with a flashlight I found the screws that held the cluster cover. Removed the screws, moved piece of trim aside and took off the cluster cover. There are only a few screws left to remove the entire cluster.
I will take photos and post them as soon as I finish. If you were familiar with the removal process, you could change a burned bulb in about 20 minutes. now that i have the cluster out, would it be wise to replace the bulbs with led bulbs? I read somewhere that the factory dimmer will not dim the led"s
Louis
Louis
I will take photos and post them as soon as I finish. If you were familiar with the removal process, you could change a burned bulb in about 20 minutes. now that i have the cluster out, would it be wise to replace the bulbs with led bulbs? I read somewhere that the factory dimmer will not dim the led"s
Louis
Louis
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08-28-2021, 06:20 PM
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Re: How to get to the check engine light - 1987 Firebird
Good deal. That's the way stuff gets done. 
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