Skip the auto shop - Our mechanics make house calls

Q: new battery is draining within 24 hrs, everything checks out ok by mechanic who is still testing more parts

asked by on

Last week went to start car & it was dead, no sounds at all. Roadside service tech jumped battery so as to move it out of my garage & onto tow truck & towed to mechanic who said 3 yr old battery was the problem, so he sold me a new one. I picked up car & went out for several hours, then home, car was fine. Next day. again car is completely dead & was retowed back to mechanic. He checked out alternator, starter, ignition, fuses and then checked "Light Control Module" & tested a new one overnight, but next day he called to say that was not the problem either, so he is continuing to check what else. Can you please give me some hints of where else to look for problems as the mechanic has my car for several days now & I need it back asap. Thank you so very much for your help..

My car has 95000 miles.
My car has an automatic transmission.

A: Hey there, It sounds like you may have a ca...

Hey there, It sounds like you may have a case of parasitic draw. This is when a system stays active and slowly draws battery power when the car is shut off. This can also be caused by the charging system not having proper output. In either case it is entirely possible the drain, over time, had killed the battery. Batteries do not like to be drained completely and will not always recover, leading to the need for replacement.

Parasitic draw cases can be notoriously difficult to diagnose. The circuit with the draw must first be identified, then once the circuit that the problem is on is identified, it becomes easier to diagnose. The draw can be caused by many things, shorted to power wiring, aftermarket stereo and alarms, ECM failing to go into sleep mode and etc... This particular situation may take the mechanic some time to diagnose but if problems persist the certified technicians at YourMechanic would love to help you figure out why your car does not start.

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

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: Do I have a bad fuel pump?

If you have tested the fuel pressure at the test valve on fuel rail and do not get pressure then the system will need to tested for a bad fuel pump.

Q: Bad noise coming from transmission.

Depending on whether you have a manual or an automatic transmission will determine what the issue is. Also, a description of the noise would help. Most of the time if you have an issue with the manual transmission that causes...

Q: Warning code P0340

The camshaft sensor is a 3 wire sensor. Power and ground need to be checked and the signal wire can be scoped to see if a signal is present as the engine is running. Generally, the camshaft sensor itself is...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
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...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.