OK great minds of the C3VR I have a problem that I cant figure out.  The problem is that my Check Engine Light (CEL) which I feel is electrial in nature instead of an engine problem.  The CEL is supposed to come on when the switch is turned to the ON position to verify that the light actually works then turn of when the switch is turned to RUN.  Presently my CEL does NOT turn on when the switch is turned to the ON position but it turns ON and stays on when the switch is turned to the OFF position, stays on even with the key out, causing a battery drain and perhaps a fire hazard.  My code reader shows no codes and the car performs like normal.  I tried disconnecting various circuits and have found that the CEL goes out when the courtesy light fuse is pulled.  The courtesy light timer is working normally but I disconnected it completely.....CEL still stays on.  I pulled the center cluster and checked the harness as well as possible with nothing unusual found. I have good electrical diagram, courtesy of Joel, but I'm no electrical engineer and find some of it confusing. I can do without the courtesy lights but prefer things to work as they should. Is it possible that the ignition switch itself is the culprit?  The ignition seems to work properly and feels "normal".  Any suggestions are appreciated.

Sounds like a ground issue to me. Does the light work properly when you pull the codes? As in, it flashes the codes? Even with no codes stored, it should flash a "12".
I'll do a little more research, and see what I can come up with.



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Joel Adams
C3VR Lifetime Member #56    
My Link


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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Thanks Joel, actually Ive been using a code reader for he codes.  Ill try the flash method tomorow and see it it acts normally.

I have a 81 with The ECM.  Do you have a ECM in the 82?  If socheck connection of the harness at the ECM.  That is where I found my problem with my check engine lite.  Sounds goofy but true !!

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Thanks Dan, Ill check the connector today while Im out there in the garage.

Latest chapter to this electrical saga...... I went out this morning to try to check to see if the CEL would flash as it should when jumped from the ALDL socket.  Turned the switch to ON and sat there for a few seconds and began to smell a sweet burning smell...stronger and stronger till I looked back at the battery compartment where there was light white smoke rising.  turned the switch off then turned the battery disconnect off.  The computer was fried...OK, perhaps this was the problem all along so off to the NAPA to get a replacement.  As a side note whoever designed the mounting location and brackets for the computer in an 82 was a sadist.  Got the new computer, transferred my old PROM chip to the new computer and got it installed, hoping the problem was fixed.. NOPE the same thing is happening as before with the CEL.  So it seems the computer frying is a symptom, an expensive symptom, of a larger problem.  So, Im back where I started... wondering if the PROM is the problem?  Replacement OEM proms are not available and I hate to spend $150 for an aftermarket performance PROM as an experiment.  I took the courtesy lights fuse out and the CEL does not light with the switch OFF but it stays on all the time the engine is running. With the new computer the car cranks and runs fine but the CEL remains ON.
Crossfire19822010-03-01 12:43:39

If you leave the ECM disconected and then turn the key on then off what happens?

With the ECM disconnected the car would run like crap!!!   If the emmissions system was not intact, that would cause the CEL to lite up also.  With the info that I have seen so far, my guess is that there is an electrical device that is ahead of the ECM that has malfunctioned.  It is just a matter of finding out which one.  I am not that familar with the crossfire system.  I have only heard that it was not all that good.  Either you had a good one or a bad one, no inbetween.  Keep us posted, I for one would like to hear how you fixed it!!

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Disconnecting the ECM would be for troubleshooting only, to try to determine if the light is being kept on by the ecm or something else keeping the light on, in hopes of determining which direction to go

Well...not to sound like I'm saying you would, or did, but...are you sure your jumpered the correct two terminals on the ALDL?
You say you have a code reader? Normally, when you have a scanner plugged into the ALDL, the CEL will also be flashing the codes, since the scanner/code reader is doing the same thing...grounding the data line. The only real difference is the scanner/reader will "interpret" the data, and give you a readable code from there, instead of having to count the flashes, and then cross-reference the manual to get the code description.
It sux the smoke came out of the 'puter, tho...
I'm in agreement with Bob on disconnecting the ECM, and seeing if the CEL will still come on. Of course, it's not gonna start, but it might confirm a ground issue with the CEL circuit...


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Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Thanks Joel, NOPE, I didnt jump the wrong terminals....I didnt get that far before I let the smoke out of the computer...didnt even have the jumper in the car.  Ill try disconnecting the ECM and checking tonight, its supposed to be a little warmer here tonight.  There is a gound point on the frame just above the drivers side courtesy light that I found on a diagarm last night, going to check that first thing.Crossfire19822010-03-03 06:31:14

Wow!! So the smoke escaped first, eh? That's not too gud! That could be a wiring problem that caused it, or it may have just took a doo-doo on it's own. However, since you replaced the ECM, and the light is still on, that would concern me a little.
I have an older Mitchell and Alldata program on one my other 'puters at home, but I gots no place to set -it up to use. Sure would help, I think. I may haffta find a spot in da garage to set it...


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Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Crossfire 1982:  Do you have a shop manual for your car??  Wireing diagram should be in it !!  Send me a pm with a good contact number for you.  I'll give you a buzz!!

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Was that battery disconnect switch part of the original acc for your car??  Or is this an after maket jober??  That may be the problem also!!!!

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Thanks Dan, I do have the factory service manual and have been pouring over the wiring diagrams, but I appreciate your offer.  Battery cut off was not original.
Crossfire19822010-03-03 14:40:36