Dead battery after car sits more than 8 hours
Asked by YoderB Nov 07, 2016 at 03:57 PM about the 2000 Cadillac DeVille Sedan FWD
Question type: Maintenance & Repair
Replaced Alternator, Battery and Alternator grounding cable. After new items were installed, took car to Auto Zone and re-tested Alternator and Battery, both tested well. The voltage while car is running stays at 14.4 volts. Checked at night to see if any lights or electrical items are running, nothing noticed. Re-checked the grounding cables for the battery and Alternator, nothing abnormal.
Is it possible even though the alternator checks out that it isn't the correct one for this year car.
Note: The Alternator was a cheap replacement that I found at Rock Auto: PURE ENERGY 15476 Remanufactured; Reman; 140 amp $104.99
6 Answers
Doubtful if it is the alternator since you are reading 14.4V when running. More likely it is something hard to see that is draining your battery when at rest. It is not necessarily a light, just an electrical module that is incorrectly working or shorted to ground. The best way to find it is to hook up an Amp meter between the hot pst of the battery and the end of the positive battery cable (after removing the cable from the battery). You should see a small but positive current flow on the meter. Then have someone pull each fuse from the fuse panel until it shuts off, This will tell you what circuit to investigate. Then you need to begin examining the wires and devices on that circuit to find the defective part. Good luck.
Thank you Taver91, that gives me a starting place. Will update if I fine anything out.
Update, It was a bad car battery (even though it was brand new) crazy readings on the voltmeter, pulled every fuse at least twice. With the new battery, all is back to normal.
hallngrass01 answered 5 years ago
I have the same problem I realized I was drawing power while vehicle was sitting from the automatic window wiper setting. I had to turn wipers completely off after hearing a hum from outside the car on a wet day. in the off position the hum was gone but I will only know for sure by waiting until I let it sit over night. too be continued.....
Remove Fuse 3 from the Block under the hood on the right hand side. IT is like a 30 Amp fuse for the Electronic Climate Control. see if that stops the dead battery and then repair as necessary if it is the issue. Does this effect your Instrument Cluster (visibility)?
Car started loosing power outta nowhere then died replaced fuel pump and fuel filter it started back up right away drove a couple hours went out this morning started it started good turned it off then restarted it and started for 2 seconds then wouldnt start at all its a 2000 cadillac deville dhs any help would be appriciated it cranks no start tho
