Hi all,

Apologies for the long message.  My 2.2tdci Mk 4 Titanium X Estate seems to have a battery drain issue.  Prior to Christmas my neighbour reported my hazards going off in the middle of the night and when I checked the car in the morning it said "Alarm Triggered". Alarm hadn't sounded but I checked by using the key and leaning in and the sounder works fine. All seemed well until the convers+ radionav stopped working.  Came back to life randomly mid drive once but hasn't worked since.  The battery then went flat over night. I charged it to full and it then drained in less than 2 days.  Suspected knackered battery as it was 5 years old, so I replaced it and the replacement now does every 2-3 days even if the car is run.  The alternator is fine and I've checked fuses for alarm and radio. I now have the alarm system service message....

 

Advice please on likely causes and how to check the alarm system and head unit for faults

Check for water ingress to the Body Control Module. This video will give you the general idea (possibly not your exact version of Mondeo):

 

16 hours ago, unofix said:

Check for water ingress to the Body Control Module. This video will give you the general idea (possibly not your exact version of Mondeo):

 

Thanks, I was hoping to take a look at the alarm module this weekend, so I'll check the washer pump as well whilst I'm there. Hoping it's a self help fix as ford guestimated circa 500 quid before they'd even looked at the car to narrowed down the issue.

On 1/24/2024 at 1:15 PM, bradders1985 said:

Thanks, I was hoping to take a look at the alarm module this weekend, so I'll check the washer pump as well whilst I'm there. Hoping it's a self help fix as ford guestimated circa 500 quid before they'd even looked at the car to narrowed down the issue.

Unofix, thanks for the heads up.  I have checked the bcm and there is screen wash on the pins.  Will try the clean up as per the video.  Dread to think what a new loom would cost and I doubt it's an easy self help fix. 

 

 

That's good that you have found the problem, but bad that it is the screenwash pump issue.

The most cost effective way is to cut the wires off a couple of inches from the back of the connector and run two new wires through to the pump. Of course the pump will need replacing (not cheap. If you're lucky you may be able to remove and clean up the BCM inside. Use lots of IPA and a soft paint brush.

38 minutes ago, unofix said:

That's good that you have found the problem, but bad that it is the screenwash pump issue.

The most cost effective way is to cut the wires off a couple of inches from the back of the connector and run two new wires through to the pump. Of course the pump will need replacing (not cheap. If you're lucky you may be able to remove and clean up the BCM inside. Use lots of IPA and a soft paint brush.

I've found a replacement pump for £15, luckily it seems to be the same dual model on Titanium's as it is most Mazda's/ Volvo's so there are plenty of spares.  Access is a pain at the front end, much less space than in the video so cleaning or replacing wires is going to be fun!

On 1/26/2024 at 2:46 PM, unofix said:

That's good that you have found the problem, but bad that it is the screenwash pump issue.

The most cost effective way is to cut the wires off a couple of inches from the back of the connector and run two new wires through to the pump. Of course the pump will need replacing (not cheap. If you're lucky you may be able to remove and clean up the BCM inside. Use lots of IPA and a soft paint brush.

 

Hi Unofix,   any more suggestions?

I've cleaned the BCM, there were no signs of corrosion on the board or BCM terminals, only on the green plug.  Washer pump had corrosion on it so I've replaced that and on that front all works fine now. However I still have the battery drain issue, less than 3 days and it's down to less than 11V whether it gets driven or not. 

Radio still doesn't work, I've removed this, checked connections and replaced all audio fuses so I'm guessing that is now dead - turns out it had been repaired in the past as it has an audio repair companies stickers and service stamp on it.

Code reader doesn't give me any faults but clearly something is staying on with a significant amount of draw on the battery

The two most common faults that cause the Canbus network to remain awake is (1) faulty bluetooth module, and (2) poor solder joints on the instrument cluster causing it to keep triggering the Canbus.

9 minutes ago, unofix said:

The two most common faults that cause the Canbus network to remain awake is (1) faulty bluetooth module, and (2) poor solder joints on the instrument cluster causing it to keep triggering the Canbus.

Is there anyway to check the BT unit? I'm assuming this is on the same fuse as the audio circuit so all I can really do is disconnect it and hope the drain goes away? - glove box is still out anyway so an easy job.

I'm guessing cluster removal will be as much fun as getting to the washer pump!

My car seems to take an age to fully shut off.   There is a constant relay clicking sound every few minutes after locking it - is this normal and what is it?

I'm at the point where the car will be going in the bin and being replaced with something that has a functioning radio and doesn't need charging like an EV with the heaters left on!

18 minutes ago, bradders1985 said:

My car seems to take an age to fully shut off.   There is a constant relay clicking sound every few minutes after locking it - is this normal and what is it?

That would be part of the problem, but you have to find the cause. The bluetooth module can usually just be unplugged. The instrument cluster is not too hard to remove, not sure of your model but normally the surrounding trim just pulls off to reveal two or four screws. There will be YouTube videos showing you how to remove it.

@rd457 offers a repair/refurbishment of instrument clusters.

Instrument cluster and Bluetooth were both removed overnight and the battery is dead once again.  

Popped out to the garage last night and he front wipers were functioning very slowly whilst the car was locked (it had been locked for 4-5 hours) - never noticed this before but they have now stopped halfway up, having drained the battery to 10.2v so this suggests a fault / short on the BCM or in the loom, probably from the washer fluid! 

Will be putting the car up for sale "spares or repairs"!  Shame to bin a car with low miles in good mechanical but I need it for commuting and don't have the time to chase a potentially very expensive electrical fault.

2 hours ago, bradders1985 said:

Popped out to the garage last night and he front wipers were functioning very slowly whilst the car was locked (it had been locked for 4-5 hours) - never noticed this before but they have now stopped halfway up, having drained the battery to 10.2v so this suggests a fault / short on the BCM or in the loom, probably from the washer fluid! 

You have a "knackered" BCM to use a technical term. Quite possibly caused by water ingress from the screenwash pump.

At least now you have a definite cause and something to replace 👍