Hello,

Over the weekend my C-max has been impossible to start due to a flat battery. It is a 1.6 petrol engine. Got the RAC out and he said that the car needs a new battery, which is fine. However he also said that there is a battery drain coming from somewhere. He said that when the meter was placed on the negative battery cable, I should get a reading of below 0.10, and it was coming back at between 0.15 and 0.20. This was after leaving the system to turn off after around 30 mins.

I have been having the tailgate problem, which seems quite common, where the boot opens on its own when the car is unlocked. Could this be the reason for the battery drain?

I dont want to buy a new battery only to have the same problem in a few weeks.

I dont know if its relevant, but I had four new brake pads fitted on Friday and this started Saturday.

Im not sure if I am posting this in the correct place, and if I am not I apologise!

Any help would be great..

Cheers Ed

If your boot solenoid has a short then it could explain the power drain.

Time to invest in an auto electrician.

Thanks very much for the quick reply!!

Thought it might be that.

Cheers Ed

I had a similar problem on my old focus, boot latch kept opening itself when driving.

I was going to pull the fuse and just open the boot with the key but it stopped of it's own accord.

Release button on the dash stopped working too so I assumed the fuse had gone and just left it for a while.

I got advice that the wires in the boot hinge area had a habit of snapping due to brittle insulation so investigated and found the wire was snapped along with the third brake light wire also.

I patched the wires but found the boot latch still wasn't operating even with a new fuse.

In the end I diagnosed a dead solenoid in the lock unit and replaced it with a secondhand unit from eBay.

Problem solved.

If you have a wiring umbilical to your boot that's the first place I'd check.

Some crimp connectors will do the job.

If you can't find the time to do it immediately I'd recommend pulling the fuse until you can check it out or you may burn out your lock like I had happen.

Which fuse is it?

Cheers Ed

Sorry mate, can't help you for definite on that one.

i'm reasonably sure the 2003 C-max has the same wiring system as a 2005 Focus and the only reference for the boot release circuit i can find is number 79 - i'm assuming fuse 79 in the footwell board?

Maybe that will give you a bit of a clue but i really can't be certain.

Edited as i just had a brain !Removed! -

Does your boot have the release switch inside a rubber bit between the plate lights?

If so the switch may be sticking inside the rubber unit.

It is a known problem on the MK2 Focus.

If you can't locate the fuse you can remove the switch unit and check if it's corroded or gummed up, if the boot opens on the key fob then you can temporarily disconnect the switch until the problem can be resolved.

That's what I was thinking of doing if I can't find the correct fuse. It wouldn't matter as I only ever open the boot with the key fob anyway. Thank you so much for the replies, I will let you know if it solves the prob.

Cheers

Hello I have unhooked the clip which connects the tailgate switch in the boot. Then I bought a new battery and checked for battery drain. I have the double bonus that there is no drain, and the boot doesn't open on it's own! Problem fixed.

Thanks very much for the help.

Ed

Glad to be of service.

The switch must be the culprit then.