Tuesday, November 27, 2012

Car Battery Leak

Battery drained overnight on vehicle.

Replaced the battery but still the problem is same with new battery.

How the new battery can drain with ignition turned OFF

I will say these problems are very rare,but when it occurs tracing the faulty is many a times very difficult.
Here in these chapter i would like to share our garage Parasitic Battery drain incidences:------

First of all , see any thing can be faulty causing parasitic drain or battery drain overnight issues.

Its not like one common fault in every case.

So once you go through few of such cases then you come to know that where exactly to look to confirm the fault of battery getting drained with ignition turned off.


In these particular case traced the battery drain to the 40 amp master fuse for the air conditioner.

Had a VW jetta do the same thing, AC relay stuck in closed position, allowing constant current flow to AC clutch. replaced this relay and voltage draw no longer there. relay has battery power without key on.

ITS ACTUALLY CALLED Parasitic battery drain


These issue was noticed on Ford Expedition vehicle./

I suggest you to remove each fuse from the fuse slot one by one and see if the Darin issue stops.

Try removing each  fuses and you will come to know  that the drain greatly diminishes when fuse #5 or any other fuse is removed.
On these particular case removing fuse #5 cleared the battery drain issue.

The circuit this fuse protects, controls a whole bunch of things--PCM, Speed control deactivation switch, Manual climate control mode switch,Brake shift interlock solenoid, EATC control head, Body Security Module, Speed control servo, Security lock LED.

The next step is going to be to disconnect one component at a time to see which one causes the battery draw to stop. As soon as you do this, you will know which direction to take next. Either that module or component is bad or that module or component is staying awake for another reason and will need to be looked into further.

On these particular PCM was faulty causing the Parasitic battery drain

The PCM is mounted on the fire wall on the passenger side under the hood.

It will have a tone of wires going to in and about 3 or 4 big connectors that plug right into it.
Replacing the module helped to clear the battery drain issue.



Mercedes-Benz Parasitic drain issue

Can be anything but on these similar case found that it was instrument cluster causing the problem causing battery to drain.

Two wires under the cluster panel were getting interconnected causing the battery to drain.

This wire was for engine compartment fuse box,and due to this battery was getting automatically discharged.

To confirm these issues on your vehicle is suggest you,
Try to disconnect the instrument cluster first and see if there is still battery draw with ignition off.

if this does not help, then you will have to start disconnecting each module until draw is gone.
Yes i agree its time consuming,but thats the only procedure to confirm which component is causing the problem.

For more get through the battery wiring diagram for your Mercedes:----

battery wiring diagram:----

These will help.

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