What does it mean when a car has a parasitic draw?
A parasitic draw is an excessive electrical load on the system that happens after the vehicle is turned off. There will be some activity and loads when you turn your vehicle off, your clock circuit for one.
What causes parasitic draw on a multimeter test?
Parasitic Draw Test with a Multimeter. On occasion, a battery may experience significant drain long after the engine has been shut off. The result can often lead to a flat, caused not by a faulty battery or through something obvious like the headlights being left on. It typically happens due to a short circuit that can be tricky to pin down.
How does parasitic draw affect the battery life?
Along with being a nuisance and potentially leaving you stranded, even minimal draw can wear down a vehicle’s battery over time, often leading to performance issues and possibly a slow death. The key to good battery life is to nip any parasitic draws in the bud and also ensure the battery keeps charge above 12.4V.
What kind of DMM do I need to test for parasitic draw?
A DMM with the ability to measure continuous current to 10A will be fine in most cases, though one rated 20A would be less prone to blowing a fuse. You also need a milliamp range for higher resolution to pick up minimal current draw as most faults tend to be of the trickle variety.
How can I find out if my car has a parasitic draw?
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. Once the reading drops, you’ve found the culprit and can take steps to repair it.
Is the same Jag has always had a battery drain problem?
Jaguar XJ8 L: The same Jag has always had a battery drain problem. Experience: 30 years of experience working with Jaguars. Independent European shop owner and technician. Hello, I’m Jason. I will do my best to answer your question quickly and accurately using the information you have provided.
When to look for a parasitic power draw?
Your battery could be near the end of its service life and it should be recycled and replaced with a new one. If the battery test shows that it is still good, then it’s time to start looking at a parasitic power draw. While you’re under the hood (or at Advance Auto Parts), test the alternator.
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.
Do you need a positive cable for parasitic draw testing?
Some people remove the positive cable to do this test, and that’s fine, but I recommend the negative cable when doing parasitic draw testing. Put your meter on the highest DC amp scale. This might require that you move your test lead to a special location on your DVOM.
How to diagnose a parasitic battery draw?
Part 2 of 3: So you have a parasitic battery draw 1 Glovebox: Sometimes you can peek through the opening of the glove box and see if any light shines through, or if you’re… 2 Trunk: If you have a friend handy, ask them to climb into the trunk. Shut it closed and have them check the trunk light… More
Where do I place my parasitic draw meter?
Put your meter on the highest DC amp scale. This might require that you move your test lead to a special location on your DVOM. Place the leads in series between the negative cable and the negative battery post and take your measurement.
What’s the next step after a parasitic draw?
The next step after you find the offending fuse is to find a wiring diagram showing what’s on that circuit. After that, it’s a process of further elimination. Unplug each component in that fuse’s circuit till the draw goes away.