Hi all,

This is my first post so I hope you are all well?

I have a MK3 Focus (2011) 49000 miles that's been doing a lot less mileage these days due to working from home etc. To ensure that I maintain the car I've been driving it once a week and checking the battery voltage periodically. With the bonnet left up, in the garage, I've notice that there’s a parasitic drain which is dropping on average about 0.3V per day from a fully charge battery.

I've run all the normal tests with a multi-meter. If I remove the sensor connected to the bonnet lock there's no further voltage drop. I've tested this over a 2 day period and the battery has maintained as steady 12.75V which is good news.

Is the issue I'm seeing normal or does this indicate an issue with the connection/sensor connected to the bonnet lock? I can leave the sensor disconnected when I'm not driving the car but I'm concerned that leaving the car outside for an extended period could drain the battery. Are they any tests I can do on the sensor itself?

Best regards,
Phil

 

what's the sensor for?
if it's the crash sensor then the airbags won't work
if it's the alarm sensor the alarm won't work
it's normally a dodgy lock sensor and the only way to fix it is to replace the lock mechanism

 

Thanks dojj.

I've attached a picture showing where the sensor is. There's a lot of grease on the lock ... dont know whether this could be creating an issue?
I dont have any issues locking the bonnet. If I open the bonnet the dash display will warn me that the bonnet is open and I can click on OK to clear the warning.
The car is not alarmed while in the garage.




Cheers Phil

 

Isn't that a bonnet open sensor? But a bit of wire in the 2 plugs.

 

The voltage you are seeing is probably the CAN network 'waking up' and putting the dash display on.

 

the sensors are built into the lock so you can't just replace them
locks are normally around the Ł40 mark so for piece of mind it's easier to skin some knuckles and swap them out
if you bridge the wire and there is no drop in voltage then that would appear to be the issue

 

just popped up on my youtube

 

Just sprayed some electric contact cleaner on the sensor, reconnected, and the problem has gone. Maybe disconnected the sensor helped to clear the circuit.

 

That is what you call an easy fix!!