Question about 1999 Cadillac DeVille

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Car just shuts down

As i am driving, the theft mode light comes on and the car shuts down and won't start again. it has been towed 2x's and they can't find the problem. this is a cadillac dealer working on it.then it will start,get it home and there it sits because it won't start again.any solutions will help. thank you!

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  • mickeydad4 Sep 29, 2008

    car was brought back to dealer with your response.he did not get a locksmith. he changed harness,couplings,ignition switch.brought car home, theft light came on again and car shut down. 3 days later it still won't start.what do you think? thank you!



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Honestly if it's a VATS problem all you need to do is use a meter to test the resistance in the ignition key (on the shaft of the key there is a small black plastic square with a thin metal wedge) Put the volt meter on oms and place the leads on either side of this little wedge in the key, once you have this reading you will need to get a resistor(s) within +/- 10%. Under the dash find the main group of ignition wires, there will be one or 2 much thinner wires cased in a black or orange tube usually they are 2 white wires but unfortunately they can very...from this point it's kind of trial and error and you must be careful because of how thin the wires are. but cut one strip the ends put the resistor in-line if the car starts you made the right choice...sauder and tape, you will want to be gentle with the resistor because they can break pretty easily if you have a couple zip ties splint them around it.....OK if you decide to do this it is making the VATS system void...and if you don't want to try this yourself bring it to a car stereo shop where they install remote starts...they should know all about it!!!

Posted on Apr 19, 2009

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If the theft light is comming on it will make it so it will not start i would take it to your local locksmith who has V.A.T.S. (vehicle anti theft system) equipment they can then read your key and make sure there is no problem if the key reads fine have them check at the bottom of the column they can hook up there machine and make sure it is reading the key to the bottom of the switch. Usually this is where the problem is there are only two small wire that go from the ignition cylinder to the harness below the column and after time they will break. Do this and it should resolve your problem. Thank You

Posted on Sep 10, 2008

  • Tim Carter
    Tim Carter Sep 30, 2008

    did he replace ignition cylinder and give you a new key?



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