1 have a 1986 caddilac deville i have to jump start it everyday it runs fine after the jump start but soon as i cut the car off it wont start anymore until i jump it again what do you think is the problem

The problem may be a bad alternator. When the battery is completely dead jump starting the car will charge the battery enough to run the car for short periods. Take the alternator to the auto parts store and have it tested (usually for free).

Cadillac Deville Overheating fix! - YouTube

? 2:04
https://www.youtube.com/watch?v=CIziYDXWBHM
Apr 15, 2013 - Uploaded by solodachamp
Im Solo da Champ owner of a 1999 Cadillac Deville sharing info on how i got my "lac" to go from ...

Caddilac with overheating problem - YouTube

? 4:30
https://www.youtube.com/watch?v=yzSQkoaVxiI
Aug 4, 2008 - Uploaded by gcastoria
Caddilac with overheating problem .... 2001 cadillac deville dhs..... 158 is about 100 degrees away from an overheat shutdown optimal running ...

Do basic troubleshooting. Spark to plugs? Fuel pressure correct? Injector pulse?

Even though my battery showed a good voltage it wouldn't crank the engine in my grand prix anymore. It wouldn't start with a jump box either. As soon as I put in a new battery it was fine.

check if any interior lights left on ,the trunk is the usual one that gets forgotten, have battery tested for charge holding and that the alternator is charging correct voltage the alarm and door locking are a symptom not the problem which is in the charging/battery

Replace the horn as it is rusting up inside and very soon will either not work or will blow a fuse.

Someone will need to check the key switch and figure out what is not getting power. Could be the key switch or a relay.

most likely need a new battery,thats a start,if not that probably altenator

Most auto stores sell a retrofit kit.

sounds like either your battery or your alternator has gone bad....if you can get it to an auto parts store they can check it out and tell you which it is or both....