Starting up my car
I left my key ignition switch on for about 30
minutes car needed a boost got it started drove it
for about am hour turn car of now it won't start
you probably killed the battery for good , they can only take so much . An event like that can be the last straw .
You have to be very careful jumping a Cadillac, especially a Deville, they blow the mains for no apparent reason, so check the main fuses then move onto the rest before doing anything else, if that checks good then get the battery checked, if it tests bad replace it, and get a good battery, preferably a sealed unit but those can be expensive, after it is running, Check the voltage at the battery, if it isn't reading at least 14.2 volts then have the charging system tested just too make sure you didn't burn out the alternator trying to charge a weak or dead battery. DO NOT disconnect a battery cable with the engine running, you can and will cause untold damage to the electronics.
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