Suspected Electric Seat Drain. Please help??

[MangoMan]

Hi.
I have seemed to got a battery Drain issue - only happened recently in the last couple of days - Basically after a short run battery shows just under 13 Volts. Within 4 hours it has dropped to 11.8 Volts. After overnight it shows 11.1 Volts. Car won't Start.

I do not think it is the battery as it looks pretty new and where I bought the car it had sat unused for quite a while. In fact between the time I test drove it and eventually took possession it sat for 5 days in freezing weather, and in fact when I went to collect it, it was covered in a couple of inches of snow! Started first turn!

It has happened in the last day or two. And in that time I have done nothing electrical for weeks to maybe cause it.

Anyway, I'm thinking it could be the Electric Seats. Mine are pretty basic, just the Seat Part is powered. Up and Down and Backward and Forward. It has no Memory Functions. Seat Back and Headrest is Manual.

What I am trying to find out is what Connection under the Seat is the Permanent Live? (A photo would be great please).
The Seats can be moved even if car is Off... I hear this can be an issue and want to try this first.

Also if I remove this Connection does it mean the Seats will not move even when the car is on?

And if this is the Drain can I wire in a Switched Live, and if so how best to go about this please?

Thanks in advance.

Edit. NB: Also I have those Seat Back Handles to make access into the Rear easier that also when pushed up or down move the Seat backwards or forwards. These seem quite floppy. Could these be a cause?
I'm just wondering because I was using these yesterday and the day before when cleaning.
Well at about 6pm I took a reading and the Battery at the Battery was 11.8, dropping from 12.6 about 2.5 hours earlier. Just after then I went, at about 6:30pm, out and played around with these Seat Back Handles and have just taken another reading, about 2.5 hours later and now it is showing 11.7 Volts.

 

[MangoMan]

Well, seeing as this has got people here stumped I thought I would add a couple more points.

Put the Battery on charge last night, not all night, just for about 3 hours. The Voltage Output before Charging was 11.78 Volts. After 3 hours of Charging it basically showed the same, 11.75 Volts... Weird..?? Instead of going up, it went down slightly! Anyway, stopped Charging, left the car connected overnight.

This morning I went out and the Battery was reading 11.78 Volts I think the fluctuation could be just my connection on the Terminals...?? So let's say the same as when I left it the previous night. Put it on Charge, a 'Fast' Charge this time. After 2.5 hours I went to check condition, 11.75 Volts. Meaning it is not taking the charge from the Charger - it is a pretty old Charger, 8+ years. Maybe more. Checked the Charger, pushing out 5 mVolts on the 'Fast Charge. Not sure if that is right...????

With a bit of luck the car started OK. Checked to output at the Battery, (a Halfords 019 Battery of unknown age) with Engine running 13.9 Volts. So the Alternator is good.

ANY comments would be appreciated PLEASE!

1) Is there an actual drain?
2) Confirm the Alt is OK?
3) Battery Charger 'US'?
4) Battery knackered?

Thanks in advance....

 

[andy27168]

In my opinion it is definitely the battery that has failed I would be very surprised if your seats are causing this (or indeed any drain at all) as the seat battery drain issue with this age Mercedes is generally caused by cars with the memory function for the seats.

 

[MangoMan]

In my opinion it is definitely the battery that has failed I would be very surprised if your seats are causing this (or indeed any drain at all) as the seat battery drain issue with this age Mercedes is generally caused by cars with the memory function for the seats.

Thanks Andy.....
I am starting to think this myself.

Although it does look pretty new...??? Would Halfords be able to tell me if it is good or not and how old it is by the Serial Number, (which is on it)?

 

[MangoMan]

Took the car to Halfords and they quite happily did a test on the Battery/Alternator and came to the conclusion, or rather the fancy machine did, that it is in a state of discharge with my driving habits, or lack of them, being the cause because the Battery itself as well as the Alternator are in good condition.

We will see after I take it for a decent run.

 

[MangoMan]

I will say one thing though.

I am quite dissapointed that out of almost 60 members who viewed this post only one kind fellow, namely "Andy27168" bothered to say anything. And there I was under the impression that this is quite a common problem/issue.

And I say this quite unapologetically....

 

[AMGeed]

^Don't be disappointed that you have had few replies. It is after all less than 24hrs after your first post.
Battery drains are ndeed a common issue, but pinning it down to the seat module isn't.
If I don't know the answer or have a clue, I won't respond. I have memory seats so mine are different to yours.That is only fair as I'm sure you don't want misleading info.
It could just be that none of the 60 viewers could actually help. There is no shortage of help here when members who do actually know reply.

 

[brucemillar]

You are confusing several issues into one and that may scare people off.

1) your battery is not charging.

2) your battery charger is 8+ years old and unknown state.

3) you don’t really know if all was good prior to your purchase.

4) assumption about seats causing a drain.

5) manual handles causing a drain.


Fix one issue at a time.

You need to definitively establish if your battery is good?

That is binary and not down to how you drive. The battery is either good (can hold a charge) or is bad and will not hold a charge.

Your charger may be adding to your battery woes. It could be causing a drain. Bin it. Spend £13 in Lidl and buy a new one.

Once you have established that you have a tested good battery and charger that maintains a charge. You can establish if there is a drain?


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