Topic: Check Engine Light not working................
in Forum: C3 Electrical
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Have replaced the circuit wiring for all the gauges but CHECK ENGINE LIGHT does not come on. Where can I get a replacement check engine assembly?
Any and all help appreciated......
Thanks,
Dan

Any and all help appreciated......
Thanks,
Dan


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I presume your car is a 81 or 82, or it would not have a yellow check engine light. Is this the one your talking about? If so, the computer controls the check engine light. Many have a lamp driver that the computer signals to turn on the light. The lamp drivers did fail sometimes, but not often. Check all of the fuses first. It may not be the same as the gauge fuses, but a computer fuse. Let me know and we'll dig a bit.
Yes they are, but are not labeled for the computer. So just make sure they are all good. I will dig up a wiring diagram to locate the colors on the light module. Silly question, did you check the bulb? I know that's a lot of work to get in the dash.
I did some checking. You do have a remote lamp driver module in the wiring harness. This usually behind the dash, but I did not find the exact location.
I printed out the trouble shooting flow chart and wiring diagram for the lamp and lamp driver. Send me your address and I will drop it in the mail. Much easier than trying to duplicate it all here. Besides, I could get into some copyright law if I posted it verbatim.
The lamp gets it's power from the 20a trans fuse. If you ground the D terminal at the ALDL (computer diagnostic link) the light should come on. This is a yellow wire. If not the problem is in the power supply to the bulb, or the ground wire from the bulb.
If it does come on the problem is now in the wire from the ALDL to the lamp driver, the lamp driver itself, or the computer control, or associated wiring.
It sounds like a lot, but it's not that bad. When you see the diagram you will see what I mean.
I printed out the trouble shooting flow chart and wiring diagram for the lamp and lamp driver. Send me your address and I will drop it in the mail. Much easier than trying to duplicate it all here. Besides, I could get into some copyright law if I posted it verbatim.
The lamp gets it's power from the 20a trans fuse. If you ground the D terminal at the ALDL (computer diagnostic link) the light should come on. This is a yellow wire. If not the problem is in the power supply to the bulb, or the ground wire from the bulb.
If it does come on the problem is now in the wire from the ALDL to the lamp driver, the lamp driver itself, or the computer control, or associated wiring.
It sounds like a lot, but it's not that bad. When you see the diagram you will see what I mean.
Ken,
Just wanted to update you on progress so far.........
Tested the check engine light by jumping the d or 419 terminal on aldl and grounded it to shifter and light came on.
So am in progress of removing the computer so i can check the connections to see if there are any loose fitting ones.
waiting for your mail to arrive.
thanks for the help so far...........
Dan
Just wanted to update you on progress so far.........
Tested the check engine light by jumping the d or 419 terminal on aldl and grounded it to shifter and light came on.
So am in progress of removing the computer so i can check the connections to see if there are any loose fitting ones.
waiting for your mail to arrive.
thanks for the help so far...........
Dan

in Forum: C3 Electrical
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