Ford Fiesta 2008 Battery Drain

[BananaRama]

Hi everyone,

For the past few weeks my Ford Fiesta has a parasitic drain issue, causing the battery to die after about a day of idling. Using a multi-meter I found a constant drain of 1.8A while the car was fully turned off and doors closed. By pulling fuses and disconnecting parts I found that both the instrument panel and the center console display are the culprits. By disabling both the drain goes down to about 0.3A (still too much). It seems that they both do not properly enter sleep mode despite being turned off. Does anyone have any clue what the cause might be? As I understand the BCM is responsible for sending the sleep signal to both units and it might not be doing that correctly. Is there any way I can test this? Might there be another issue that is causing both the instrument panel and the display to drain so much?

 

[BananaRama]

Upon further trouble shooting it seems like I can also turn on the radio with the key removed from the ignition. Seems like it does not properly register shutting off the car.

 

[Handy Andy]

Might want to check those Relays - although a long shot, the wiring harness can possibly have a short caused by corrosion in the connection points - so some connectors you can get at - monitor the drain watching that meter - and if it stops (drops to zero or thereabout) when you separate a particular connector - the condition exists in that harness and it's parts that connect to those wires.

Also the sections you mentioned - one being the radio and much of the console, might be due to a faulty entertainment system using capacitors that are drying out and creating a load on the electrical thru the "keep alive" memory or settings in the main stereo head unit. Although it can be fixed, it is not easy and to locate the technology of that era to replace those particular parts is not an easy task - thinking older radio shops - which their herd and parts resources are getting thinner and thinner.

Being it's 2008 finding a working stereo Head unit might be a hard one to locate - only way to verify that the head unit is causing this; is to find the harness pull it (by taking apart the dash to remove the radio to pull it's harness) and or it's particular fuse and see if the meter agrees . The problem here is the latter models use a separate module as a means to store settings and add versatility. Using Ford's infinite wisdom - they abandoned the older Ford Audio System for a newer type of infotainment called SYNC that was originally developed thru a joint venture with Microsoft as a means to expand a vehicles likeability and ability to entertain using various media formats. Didn't seem to last long as for the platforms and their support also got left behind.

So the main culprits are corroded oxides left on connectors, onto failing wire insulation or bad parts that are supposed to hold a charge are now demanding more power to "Hold their charge".

 

[BananaRama]

Thanks for the reply! I just disconnected the radio fuse, but the radio just keeps playing. I am assuming it is not supposed to do that? I will test completely disconnecting the radio unit and hopefully that will fix the issue. I also checked all the relays in the engine compartment with a multimeter, but they are all in working order.

Edit: I forgot to say in my first post: the issue coincides with the AUX audio port dying completely so your radio theory might be correct.

 

[Handy Andy]

You have TWO radio fuses - one for "keep alive" while the ignition is off, then another for when you power the audio amplifier - which is protected by a separate fuse.

F18 - protects Radio and DTC (Diagnostic connector) - 15 Amp
F44 - same thing - only it's 3 amps

 

[BananaRama]

After replacing the radio with a car play the drain went down to 0.8 when the car is off, but that's still way too high. Aside from the audio AUX not functioning the indicators also intermittently blink fast while driving through the dark. I replaced all of them and during the day they work no problem. I am guessing something is drawing a lot of power no matter what, but I have no clue what it could be.

 

[scotman]

You should connect a voltmeter to the battery and then start pulling out fuses starting with the audio system and then the anti theft system and so on..

 

[Handy Andy]

As per @scotman suggestion, can you cobble an older cigarette lighter adapter and hook up to a voltmeter thru it's test leads - one of those digital ones.. not just a battery voltage minder meter - they work but may have too slow of a response time.

I mean, this may be something as simple as a wire crimp that is failing onto a major support failure that is imminent due to a plastic box or bracket getting ready to break (thinking fuse box and it's holders) - the cigarette light connection being heftier than a simple wire to the battery - might show this change due to the length of wire and it's voltage drop - and since it's by the radio - it offer a more convenient connection point and supplied by the same power feeder lines causing this.

Why? Well, if you hit a bump and this spikes the system due to loose wiring or issues similar - you may not notice the spike unless you have some type of fast tracking metering system on the lines to find the spikes as they occur and when it happens what was the vehicle doing or traveling over - to make it do this?

You can see the changes faster on a meter that is fast tracking and if it has the feature, even can show RMS to Peak as a meter movement or indicator to show changes so you can see them easier.