No Start, Theft Issue? | 1992 Cadillac Eldorado

This case study took an unexpected turn that could only happen in certain areas of the country. 92 eldorado wire diagram bi 300x232 PhotographThe vehicle in this case study is an 1992 Cadillac Eldorado. 92 cadillac eldorado big 300x240 PhotographWhen this car was dropped off, I was told that it was a no start caused by the anti-theft system. The first step I took on this one was to confirm the no start. I turned the key to the run position and nothing happened besides power being cut to unnecessary devices. Next step on my list was to check for codes, none present. So I decided to print out the starting system electrical diagrams. The first image is the diagram I used.

Power goes from the battery, to fuse, to ignition switch, to the starter enable relay that is controlled by the pass-key decoder module. Then the power goes from the starter enable relay, thru the transmission position switch, to the the starter. I diagnose electrical problems 3 ways; #1: by finding the easiest testing points, #2: by testing at 92 eldorado relay location  300x240 Photographpoints in which multiple tests can be performed, and #3: by going to common failure points.

After looking at the wire diagram on the starting system, I choose to use #2. I saw the starter enable relay as a great 92 eldorado relay conn big 300x240 Photographplace to check for power after the ignition switch, check to see if the anti-theft system was enabling the starter, and I was able to jump power to see if the starter would engage. Testing from here let me divide the circuit into 3 smaller circuits and to also check for the three things this circuit used. Power, ground through the starter and the anti-theft enable. I figured I would also be using my 1st way to diagnose but when I found out that the starter enable relay was under the driver side carpet I knew it wasn’t my 1st way but it was my 3rd way. How many corroded wires and bad grounds have you found under carpet? I sure have found my share.

As I started pulling trim off and started pulling back the carpet I ran in to something not everyone gets to see. This car was just pulled in out 0*F weather and the carpet was completely frozen rock hard. I had to pry back the carpet far enough to get to the relay and connector. I then check the relay for power at terminal 1 and 2. 92 eldorado relay big 300x240 PhotographThen I checked to see if the pass-key decoder module was actually trying to ground out the relay, which it was. 92 eldorado sunroof big 300x240 PhotographI finally jumped power from terminal 1 to terminal 4 which engaged the starter. Now I know that the power supply circuit, anti-theft system, and the rest of the starter circuit are all good besides the relay itself all at one location. The problem with this car was that the relay filled with water from the sunroof that was missing and then it froze solid. You think they see that in Arizona! The relay still worked after I thawed it but it still got a new one and off it went.

Leave any questions or comments below. Thank you.

12 comments

  • I have a 92 eldorado n my auto theft system came on it won’t start n it also has not been driven or started up since july of 2012 n I dont know what to do I need help bad please email me

    • Travis Dewitz says:

      You need to have the system diagnosed by testing. Start with your powers and make sure your chipped key is good and that the signal is making it to the theft module.

  • Erick Wingfield says:

    I had the same problem but it happened in a day car was fine up until yesterday came out the store wouldnt start sat for a while then it started right up drove it home turned it off tried to start it wouldnt start was haring clicking from my side along the seat when i was trying to start it so i put up the carpet to see where the clicking was coming from found the relay didnt know what it was can inside found your site low and behold you had a car on there same year as mine 92 cad i eldorado its been cold out here like 10 and 20s Thanks for the help

  • I can’t find the ignition relay anywhere for purchase. Where did you get the replacement? autozone doesn’t have it nor does any online sites I could find. Please help, I’m 99% sure this is the problem with my 92 eldorado.

  • Matt Eggleston says:

    Is it part number D1483C ? It’s hard to tell on the acdelco website.

  • Matt Eggleston says:

    I did find it. The original part number is 14100455 It has since been replaced by a new part number, which I don”t have offhand. I replaced it but it wasn’t the problem. I had a wiring harness come loose and was resting on the exhaust pipe, it melted and also the insulation around a bunch of wires. Things were shorting to different circuits and blowing various fuses. Cost me $550 all labor to fix it. Could have been much more. Got lucky. On the relay: It’s a multi purpose relay used in many cars. Here’s some pics and links

    https://www.google.com/search?q=relay+14100455&client=firefox-a&hs=q1o&rls=org.mozilla:en-US:official&channel=rcs&tbm=isch&tbo=u&source=univ&sa=X&ei=7mgfU83IIOrAyAG7r4HYAQ&ved=0CHgQsAQ&biw=1024&bih=607

  • kiara says:

    I have a 1997 Cadillac Eldorado. I had a used computer put on it,& every since then it been reading “Theft System Problem,Car May Not Restart”. It did that for 3 weeks & it finally did not start yesterday. Horn wont blow. Please help me

  • daniel ulloa says:

    i had cadillac el dorado 1992 the car star engine and run for half milles the engine come to be off and is hard to starting again

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