Cadillac Repair: 1990 cadillac deville that wont start, volt ohm meter, mechanic shop

Question
Car will not start with key. Mechanic shop starts it by putting jumping cables on the battery and the other on starter wire. It will start that way and you can turn it off with the key. Has tried new starter, ignition switch,relay switch. He has no idea what the problem is. However, he says it's not a lock cylinder problem where the key cannot be read. Please help. Need car for doctor appointments. Any assistance will be appreciated.

Answer
Sounds like a PASS-KEY security problem.

If you are mechanicaly inclined or know of someone who is, You will need a DIGITAL VOLT/OHM METER, Simple electrical schematics, Test procedures and picture locations of the components within the system that is causing you problems of which can't be done on this website which only allows one picture. I do not have a website so you will have to e-mail: onlineautohelp@msn.com in order to obtain the information necessary to fix your vehicle.