Happy Bank Holiday All,

I have an 09' Ford Fiesta Zetec which suffers/suffered from a parasitic drain. After battling the drain, I have decided to upgrade to a larger battery to make the problem less noticeable. Let me explain the situation so far...

In October 2021, the car failed to start *the usual dashboard and instrument panel repetitive click and flash*. I decided to swap out the "Halfords special" for a BOSCH S4 TYPE 063 44AH 440CCA (207x175x175) - a mistake already, I know.

2 months later I encountered the issue again - a dead battery (click, flash). After scouring YouTube and posts from this very forum - I self diagnosed the issue down to 3 issues:

1) Faulty Alternator

2) Faulty Voltage Regulator inside Alternator causing the battery to be overcharged - premature ageing of the battery

3) Parasitic Drain

I removed the battery from the car, charged it using an Automatic Battery Charger till 12.7 volts. Put the battery back in, fired up the car - and the volt reading was 15 volts. Quite high and so at first glance I assumed it to be the voltage regulator (overcharging the battery.. premature ageing). Took it to my trusted mechanic - he kept the car for a few days to monitor the voltage and to check the alternator. Got the keys back with 'nothing to worry about mate'.

Fast forward many weeks, you can probably guess what happened - a heartbreak. Issue 3 was now my key focus and I elected to pull fuses this time. With the battery fully charged and re-fitted, the multimeter set to Amps and my Dad on hand to 'pull' - I was feeling confident. We put the car to sleep (tricked the door locks and bonnet latch), waited 20 mins and it was go time. The draw before the exercise was 1.2 amps (alarming to say the least) and after pulling Fuse 7 (60amps), the amp draw dropped to 0.6 amps giving me some direction - still very high, I'm aware. Fuse 7 lead me to the Passenger Compartment Fuse Box and it was time to start pulling once more. By pulling on Fuse 20 and 21, the draw dropped further. The drain was isolated to the Multi-Functional Display/HVAC panel and the Audio System/Bluetooth.

The draw was more considerable on Fuse 21 and so I decided to reconnect Fuse 20, supplying power back to the Multi-Functional Display/HVAC panel (sensible). With no access to the radio, I decided to go a step further by disconnecting the Bluetooth module situated under the dash (did nothing but psychologically it did wonders).

All good things come to an end and last week, I was left without power. Up until this point, I was driving without radio and there is so much money/time you can throw at a car. Upon further investigation, I noticed that I could have done better with my initial battery choice for starters. Kwik-fit, Halfords and Euro will recommend the smaller size battery but Diesel (and perhaps ST) Fiesta owners are rocking 278x175x175 - I was curious about the gap in my battery tray.

And so, I would be very grateful for any suggestions/comments regarding the parasitic battery drain or for any battery recommendations.

Currently looking at the Yuasa HSB010 75AH 710CCA

Thanks all.

Can I ask a probably daft question, considering the year of the car, but does it have keyless entry? I've seen the keyless cars doorhandles not go to sleep when locked, and draining the battery. Its also possible something else on the canbus is still active when the car should be asleep (which is what the rogue handles do) so it my be worth checking for activity on the can hi and can lo pins of the OBD connector when the car has been shut down, should be asleep, ultrasonic sensors if fitted, taped over, door locks rolled etc as before. 

Once you know if you DO have canbus activity while the car should be shut down, then you can pull fuses for each module until the canbus pins go quiet, and that would be the real culprit. A 'scope would be best, but a meter would do - google for canbus voltage levels when active and shut down, I think it is pretty clear whether something is active or not. Something like 2.5V steady when idle, and 2.5-3.5V varying constantly when active (obviously a lot easier to see "data" with a scope)

But still probably pretty obv if the meter is flickering between the two voltages, between can-hi & gnd or can-lo and gnd. Also which bus is active would lead you to the rogue device, if you have forscan, you can see which devices are on the low speed or the high speed bus. Also this will be documented online somewhere.

Have a look here, might help:

https://support.enovationcontrols.com/hc/en-us/articles/360038856494-CAN-BUS-Troubleshooting-Guide-with-Video-

 

Scott not a daft question at all and I really appreciate the comment you left. Confirming my car does not have keyless entry - manual key, ignition in barrel, no start/stop button.

If you spend a little money and buy the new 'vLinker FS' lead and download the software FORScan on to a laptop you can then use live data monitoring to see what is still awake on the canbus system and stopping the car from going to sleep.

My thoughts are (a) The bluetooth module (b) GEM / BCM problem (c) Instrument Cluster

Please don't start guessing as it can get very expensive very quickly.

The bluetooth modules are a very common problem on many Ford models and often do not shut down fully, which causes the canbus system to remain live which in turn keeps other modules awake.

The GEM or BCM which is part of the passenger compartment fuse box is a known source of problems on your model due to water getting in and causing corrosion. Disconnect your battery first. Then disconnect all the plugs from the body control module. check for signs of greenish corrosion on any of the pins, and/or any signs of water.

lastly, the instrument cluster or your car is of an age to be made at a time when Ford were using poor solder which has caused many problems with the IC, these sometimes cause the security part of the IC to remain active.

Down load FORScan (it's free): https://forscan.org/download.html

Buy the new 'vLinker FS' lead: https://www.amazon.co.uk/Vgate-vLinker-Adapter-FORScan-MS-CAN/dp/B0952P4MLP/ref=sr_1_2?crid=8ESM5DDDYGAL&keywords=vlinker+fs&qid=1651603065&sprefix=vlinker%2Caps%2C131&sr=8-2