W202 new battery woes

[beeps]

Why is nothing simple? In nearly 40 years of motoring, I've never experienced the problems I'm getting now having just fitted a new battery to my 1999 220cdi. Basically, the central locking doesn't work or nor do the driver's side windows; neither the boot release button, but I could live with that. It's not the battery despite being Halford's (looks like a Varta as its made in the EEC and the casing is virtually identical to the MB (Varta) original) - it's got plenty of guts and I can't resolve the problems with the engine running at reasonable speed. I've tried disconnecting and reconnecting the battery but to no avail. It may be that driving the car as normal may restore the functions but I hesitate to do this at this stage in case it does something unpredictable, eg like stopping!!
Any advice would be much appreciated!
beeps

 

[Darrell]

Check the owners handbook.Something needs re-setting and it is quite straightforward.
This happened to me when I swapped the battery (for a Halfords item).
If you haven't got the handbook tell me and I will dig out mine.

 

[BlackC55]

Check the fuses.

I suspect you may have blown one or more.

 

[television]

Fuse 8 in the fuse and relay block controls the drivers window and the central locking, its an 30 amp fuse

 

[beeps]

Many thanks for your quick responses, they were all much appreciated. There was a blown fuse (#7 in the boot associated with the alarm system) but I'm ashamed to say that the main cause was that the fixing for the supplementary cable on the battery positive was (cough..) slightly less than finger-tight; strange though that it only disabled the O/S windows and not the N/S.
One good thing about this episode is that I was obliged to unstick the driver's door & boot using the back-up key; I'm glad I've done when I've had the time, tools and WD40available, it was an interesting experience and not one to do in an emergency on a dark night! I'm going to include manual checking of these locks when I do the B-level services in the future.
many thanks to the regulars who make this such a valuable site!
beeps

 

[beeps]

Woes continue.....

Looks like the original problems I experienced with the central-locking, O/S windows (and boot release) were not just down to the loose connection on the supplementary cable to the battery positive. Following my last post where I reported everything working normally, got into the car on the following Monday and the original problems re-occurred. That was 4 weeks ago. Now having recovered from real 'flu (as opposed to man-'flu!) I find car electrically completely dead; doesn't respond to ignition key and no lights etc etc. Assumed battery dead, disconnected negative and connected battery charger; ammeter gives only slightest twitch even on fast charge so assume battery is fully charged. Your collective thoughts, as ever, would be much appreciated. beeps.

 

[television]

Or if not charging, the battery could be completely flat, and it may require a higher voltage to get it going.

Or was a low battery causing all of the faults before

 

[beeps]

Hi Malcolm. I don't believe low battery voltage is the cause of the problem. The (new) battery had - a month ago - a very strong cranking action, far stronger than the old one. And I've never had problems with the battery charger, it's a high quality German one which will deliver up to 11 amps on fast charge. Today however, the ammeter needle barely moved when I switched from 'normal' to 'fast' charge, hence my assumption that the battery is fully charged.
I've read posts about SAM failures consequent on battery changes etc, not something I was aware of until this evening. Is this something the W202 is vulnerable to and if so, could you tell me the symptoms? Thanks, beeps.

 

[television]

Its too early to say yet,, the problem here is that if the car is dead, well so is the battery now,,if it has been like it for a few weeks, it can take time to get it charging again.

The headlamps should work if the battery was OK as there is nothing in the circuit to stop this.

I would leave the charger on max for a few hours,,the 202 has no real SAM problems on this score

 

[beeps]

Many thanks Malcolm. I'll persevere with battery charging tomorrow and I can test the charger on the old battery which I've still got. Your advice that the headlights should light if the battery is good (and presumably all relevant fuses are OK) is a key statement.

Thanks for the advice on the SAM. beeps.

 

[anyweb]

my own experience with my W202 was the following:

* if the battery lights the headlights but cannot start the car and its charging ok then the battery is duff

* if the battery is duff then you will have problems starting and all sorts of other electrical issues

so, either check your battery or check you alternator

cheers
anyweb

 

[beeps]

Thanks for your thoughts guys. Malcolm, you were right, the battery was flat; I re-connected the charger, zero current flow initially but cranked up to a steady 7 amps after 60 secs or so. After an overnight charge, car started easily but I'm back with the original problems I encountered when I fitted the new battery, that is, no central locking, O/S windows won't work - despite applying the procedure that you and others have described - and non-functioning boot switch. Curiously, all these functions returned once I started driving the car but then failed again following non-use of the car over a week-end. Took the car for a drive just now but no effect on the wayward functions. All fuses are good. Any further thoughts? Thanks as ever, Brian.

 

[television]

Dont know where we got to on this, but it is worth cleaning the fuse holders with a non drying switch cleaner, or there is still a poor connection somewhere

 

[bigasotonuk]

I wonder if this could possibly be caused by a faulty door control module?

 

[beeps]

Thanks for your thoughts Andy. It's bizarre. I'm convinced it's a resetting issue since the problems all stemmed from the change of battery and did actually resolve themselves for a short while. I then left the car over a week-end and the problems re-appeared. I do have a cheap (Carsoft 7.4) diagnostic kit which I bought on ebay some while ago. I've never used it and don't know whether it would be able to identify this kind of problem. Any thoughts would be appreciated. Brian.

 

[beeps]

Since this is the first time I've visited the forum since my last post, I thought I should explain how this particular problem was resolved. It turned out that in fitting the new battery, I disturbed the connector to the adjacent fuse box and the missing electrical functions were all restored by simply ensuring that said connector was properly engaged. Thus all very mundane and thankfully nothing to do with expensive SAMs blowing etc but nevertheless one to be aware of when fiddling with the battery!

regards to all,
Brian.