Skip the auto shop - Our mechanics make house calls

Q: Can't find a parasitic drain?

asked by on

I have went through the fuses looking for where the drain is coming from, the only thing I haven't checked is the amp. But I rarely tour stereo on, could this still be the culprit?

My car has 152400 miles.
My car has an automatic transmission.

Yes, your amp could be staying on. Feel it and see if it’s warm. Disconnect it to confirm. Using a low amp probe (amp clamp) around the battery cable is the easiest, most repeatable method to measure battery drain. Measure the B+ wire at the alternator as well. Feel relays for warmth and key out of the ignition while doing this. Remember it can take 10-30 minutes after running for all modules to go to sleep. If you pull a fuse then put it back it can wake up a control module. You have to leave it out and move on with testing. Instrument cluster and rear wiper motors are a possibility, too. There is a lot of electrical content in your car, so you may want to double check the fuses. You’ll also want to verify whether the battery really is good! If you are still having trouble, you can always get a certified technician from YourMechanic to come to your car’s location to diagnose your battery and let you know what needs to be fixed.

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: Air volume and air distribution controls not working in mercedes c320

The most likely cause of this issue would be the climate control unit. The mode door actuator can prevent the different distribution zones from working properly. The blower motor or blower resistor can cause the fan speeds not to work...

Q: My car won't start and is completely silent.

Sometimes electrical components in the ignition cylinder can cause this type of problem; while in other cases, the starter, starter relay or ignition coil can be the reason why your Jeep is not starting. The best way to save time,...

Q: A fuse kills the battery when it is left in.

It is difficult to answer without knowing whether this is a factory courtesy light. If in fact it is, the ground control side of the light should be a part of the dash light dimmer switch. This switch is an...

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...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...