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How do you find parasitic draw?
Pull the negative off the battery. Put the test light between the post and the ground wire. If the light illuminates, you have a draw. Use the fuse pull method to find the draw; when the light goes out, you found the draw.
Can a bad relay drain your battery?
A failed ECM power relay can also cause a battery drain or dead battery. If the relay shorts it can leave power on to the computer, even when the vehicle is turned off. This will place a parasitic drain on the battery, which will eventually cause it to go dead.
What is an acceptable parasitic draw?
A normal amount of parasitic draw for newer cars is between 50-milliamp to 85-milliamp current draw. A normal amount of parasitic draw for older cars is a reading less than 50-milliamp. Anything past these amounts indicates an electrical issue and should be addressed by a mechanic.
What should parasitic drain be on Jeep Grand Cherokee?
Before we get into this month’s Diagnostic Dilemma, let’s review some points from my March, 2016 column about diagnosing battery drains. As a general rule, a “parasitic drain” of less than 30 milliamps (mA) is normal for most vehicles 15 years old and newer.
Why does my 1998 Jeep Grand Cherokee drain by itself?
A 1998 Jeep Grand Cherokee has gone through 3 batteries in the last 3 months. While they have all been replaced by warranties, it’d be nice to get the problem solved permanently. I’ve tested the alternator, and it’s not defective. I’m suspecting it might be a short somewhere in the system.
How long does it take to drain a Jeep Grand Cherokee battery?
“Doing the math” will help define the type of battery drain we’re dealing with. If a fully charged automotive starter battery rated at 60 amp-hours is subjected to a constant drain of about .250 amps or 250 milliamperes (mA), it would take ten days to drain the battery to a threshold value of 10.5 volts.
How many batteries in a 1998 Jeep Grand Cherokee?
A 1998 Jeep Grand Cherokee has gone through 3 batteries in the last 3 months. While they have all been replaced by warranties, it’d be nice to get the problem solved permanently.