What process can be applied to isolate a parasitic draw?
Open the door, and tape the door switch open circuit so that the system returns to sleep mode. Then, remove each fuse one at a time to isolate the circuit causing the draw. The under hood fuses can be removed without too much difficulty, and without waking up the BCM.
How to find the cause of parasitic battery drain?
Luckily, you can usually find the cause of a parasitic draw yourself. Start by connecting a digital multimeter to the negative battery terminal of your vehicle. Then, remove the fuses one at a time while watching for changes in the multimeter’s reading.
What should my parasitic drain reading be on my car?
On a vehicle without a parasitic drain problem, this current is within a range of about 50 milliamps (mA). On a vehicle with a parasitic drain problem, this current will be higher than the normal range. Reading within range: If your reading is within range, you’re probably dealing with a faulty charging system or battery.
Why does my car have a high parasitic draw?
High parasitic draw is a problem because the car battery continues to drain without the alternator recharging it; this can cause the battery to go flat, leaving you with a car that won’t start. To avoid the chance of a flat battery, it is important to fix any electrical issues that are causing high parasitic drain.
How to get rid of negative battery drain?
Remove the negative battery cable from the negative battery terminal. Find the negative cable, which will be marked with a minus sign (-) and may have a black cover over it. Remove the cover, if applicable, and use a wrench to unbolt the negative cable from the terminal.
When to look for a parasitic battery drain?
A parasitic drain is when an electrical device is using battery power when the car is closed, and the ignition key removed. Therefore, when doing this test make sure that the dome light, under hood light, trunk light, etc. are off.
How to fix a parasitic drain on a multimeter?
Disconnect the negative battery cable. On the amperage side of the multimeter dial, set it to 20 amps. Disconnect the negative battery cable. Touch a lead to the negative battery cable terminal. Touch the other lead to the negative battery post, completing the circuit within the multimeter, which will display the amp draw.
What kind of drain does a car battery have?
This type of drain is called a parasitic drain. Parasitic drains below 75 milliamps are normal, but any parasitic drain over 75 milliamps will drain the battery quickly.
What is the purpose of a battery isolator?
A battery isolator can eliminate the problem of battery drain all together. The isolator’s role is to allow the alternator to assist with charging the primary battery, while at the same time not allowing other loads in the charging system to drain the primary battery.