Skip the auto shop - Our mechanics make house calls

Q: Battery drains overnight - 1990 Cadillac Allante

asked by on

My car has gone 154,000 miles. It's been running fine with no major problems. However, there is the issue with the battery drain. The car battery is new. I checked the alternator as well and it works correctly. The battery still gets drained after the car sat for the night. All the lights turn off when I turn the car off. There is nothing obvious that could be draining the battery. Do you have any idea what could casue this?

A: This problem can be diagnosed by connecting...

This problem can be diagnosed by connecting an ammeter to the positive (red) battery cable, observe the current drain (likely less than 1 amp). Then, one at a time, remove each fuse, check to see if the current drain has dropped to near 0, then reinsert the fuse. This process should identify the faulty circuit in most cases. A professional mechanic, like YourMechanic, can perform this procedure for you, and replace/repair the failing component.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Car wont start 1991 Ford

Hi there - regarding the whining noise - your alternator may have bearings that are failing. It may still charge properly (for a while), but will fail at some point. Check your power steering fluid level as well - low...

Q: Alternator problem, the wipper stops as soon as you take it to the highest,cracking sound in the morning that stop after cluching

Hello. From what you describe it would appear that the vehicle is experiencing more than one issue. The first thing I would address is the alternator, as a faulty alternator can leave the vehicle stranded if the battery dies. I...

Q: Lights won't go off

In order to diagnose the lights staying on the systems would need to be scanned for body control codes. The light control module is the most common cause of the lights stay on but a complete diagnosis would be needed...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...