2001 DTS : battery drained overnight (aprx 10hrs) battery is less than 8 months old & tests as good? other factors to consider: i've thoroughly checked all fuses today (only 1 for cig lighter bad/replaced), not sure how to test relays no window works the last one (driver) quit 2 days after I forgot to put window up when pouring rain about 1 month ago seems many electrical issues have arose in the past 2 -3 days, i don't understand why or what happened or what to do to fix PLEASE HELP knowledgeable Cadillac people, Thanks!!!

Testing for Battery Drain - Randy's Repair Shop

randysrepairshop.net/testing-for-battery-drain.html

Instructions for measuring automotive battery current drain. ... Excessive current drainwill usually result in the battery running down overnight or within a few days. ... Many digital meters have a 2 amp internal fuse that may blow if multiple ... If pulling fuses and circuit breakers doesn't stop the current draw, you'll need to look ...

How do you trace a drain on the battery of your car with an ...

www.instructables.com/.../How-do-you-trace-a-drain-on-the...

InstructablesApr 13, 2011 - I know this is an old question, but I that if the battery cable is not clean or .... I wish I could find one of those 14.4 Vdc 2 Amp solar chargers. ... be to pull a different fuse every night (not the ones which would require factory help ... As others have pointed out, the LED will not drain a good car battery overnight.

Diagnosing A Car Battery That Runs Down

www.aa1car.com/library/battery_runs_down.htm

I experienced the exact problem with my 2001 DTS. The solution that worked for me is as follows:
- spray some WD40 lubricant into the keylock
- work the key in and out of the lock assembly several times
- spray more WD40 lubricant into the keylock
- continue to work the key in and out of the lock assembly
- the key should eventually insert all the way into the lock and turn the lock assembly
I hope this works for you.

DOES THE VEHICLE MAKE ANY NOISE AT ALL WHEN THE KEY IS TURNED?, IF YOU GET A "CLICK" BUT NOTHING ELSE THEN THE STARTER IS JAMMED, GET A HAMMER & GIVE THE STARTER A FEW SOLID FIRM BUT NOT OVER ZEALOUS WHACKS, MAKE SURE THE BATTERY IS FULLY CHARGED & TURN THE KEY, IF ITS ANYTHING LIKE ALL THE CARS I'VE HAD OVER THE YEARS IT WILL MAGICALLY SPRING TO LIFE - IF IN DOUBT - GIVE IT A CLOUT!!

Here are the general instructions to find a battery parasitic drain, it is different for each problem and there is no magic bullet fix.

Instructions

• Charge your battery if necessary. Dead batteries (and even weak ones) don't give accurate results on a draw test. The dome light is a good indicator of battery strength. If the light is weak, pulsating or refuses to turn on, you'll need to charge the battery.
  
• 2Shut off everything in the car. Pull the keys out of the ignition. Ensure all service lights are off, lighted compartments closed and doors shut. Open the hood, and disconnect the trouble light underneath if your vehicle has one. Wait for 30 minutes before moving on to Step 3. (This enables normal drain from interior components to finish cycling.)
  
• 3Set your battery tester to 10 amps DC. Disconnect your positive battery connection (red cable) and position it safely away from metal components. Connect the meter's positive probe to the battery's positive post while simultaneously holding the negative probe in the air; keep it away from anything metal.
  
• 4Place the negative probe on the end of the removed positive cable to complete the circuit. Yes, you're putting a negative on a positive. Yes, this is ok. If you have a severe drain, you're likely to pop a fuse or two-identifying your problem.
  
• 5Check the meter reading. A normal reading is usually under .035 amps. If you have a minor drain that causes a higher reading, you'll need to check each component.
  
• 6Remove the first fuse in the box, and check to see if the load problem is resolved. If not, replace the fuse and check the next one. Repeat the process with all fuses. If the fuses check out fine, you have a wiring problem.
  
• 7Remove the tester and reconnect the battery. Follow the hot wire to the next connection. Remove the positive cable and connect the positive probe of the tester in its place. Connect the negative probe to a metal object. Check the meter. If the drain isn't resolved, reconnect as normal and follow the hot wire to the next connection. Repeat this step at each connection point until you narrow down the problem.
  

Duplicate posting

Buy new battery
ampifiers take little current to rise the voltage
also look for unwanted bugs xD

Very weird - I had an older VW bug that was like that, but it was usually during the winter - so unless you're in Alaska right now, I don't see cold being a factor. Is there a possibility of any condensation/moisture settling on anything (electrical connections mainly) under the hood overnight (maybe it evaporates after the car sets in the sun for a few hours)? When you say it won't start - is it getting any juice at all or just clicking/dragging like a dead battery or starter? Or do you mean it just won't fire up - like maybe it's flooded or has an ignition issue?
Check for a good/clean connection on your battery terminals.Make sure it's on good & tight, then try to start the car - if that's not it. Get a jump, then go to Auto Zone, O'Reilley's, etc and get the battery & the starter checked. I'm betting it's either a poor connection, bad battery or your starter is going out (or possibly the starter relay switch). Also consider getting the alternator checked. If it's going out, then it's causing the car to run more off the battery vs. charging the battery up while you drive. Sometimes when one of the three (battery, starter, alternator) is going out - it can cause all three to act up or also eventually go out. And it's frustrating, because any one of them can test test ok right up until the minute it just dies. Sometimes (if you can afford it) it's better to just replace all 3 at the same time - at least then you know they should all be good. Start with your connections - that's the easy fix.
If you have juice, but the car just keep turning over without firing up - consider a good tune up or get your injectors cleaned up. To prevent gunk from building up in your fuel system, consider using a fuel additive from time to time. I use B-12 Chem-tool or Marvel's Mystery Oil. You might also get a diagnostic run on it & see if any codes pop up - maybe a chip freaking out somewhere. Good Luck.

First have your battery load tested, and your alternator checked for proper charging amperage. If that is ok then you have what is called a parasitic drain that is draining your battery overnight. A parasitic drain test will need to be ran and repairs made.

Good luck. i hope this helps.

Most cars now have many modules that incorporate "memory" systems that require a constant low voltage supply, including your radio. Most batteries will hold enough charge to last a month without going completely dead. Not sure what you consider "extended period".
If storing for more than a month, you could either put a 2 amp "battery tender" on it or disconnect the battery (but you need to know how to re-arm the security system so when re-connected it will start).

If the battery is going dead in a short time (two weeks or less) have the battery load tested after getting it fully charged. It may be good enough for day to day use but if it's not in really good condition it will get low quickly.
If you have a drain that's unusual, that will require going through the entire electrical system fuse by fuse 'till you find the drain source. At this point it can be so many things that commenting is foolish as testing is the only way to verify anything.

Either you have an electrical drain - or the battery needs replacement.
If the battery is over 5 years old - consider a new battery. If you have a test meter - remove the +ve with ignition and all other systems off. Use the meter to measure amps between +ve cable and battery +ve.

Possible causes of drain are a security system that never goes into sleep mode - or entertainment systems incorrectly wired - even CD changers stuck.