Alternator or Battery?

[jadefox]

ooooooooh - do I post this here or in Electrical category?? It's too much for my brain to take on a Monday morning.

Anyway - please can someone help me with some advice? And I really apologise for the length of this post

As some of you already know from a previous thread, I've been having a few Electrical gremlins in my car for the past 6 months or so.

History:
I have been having brief one off problems with the electrics - it started with the windows - just one day, the automatic "up" function wouldn't work, just refused to "auto up" on the button all day, the window would open and close as usual though. The very next day, the gremlin had dissappeared and it's never done that since.

The next thing to mess around was the wipers. Was raining and they were going up and down but when I was stopping at traffic lights or a junction, they were stopping just short of their down position. That happened on and off periodically for a few weeks - then it stopped and they are working perfectly fine now.

Third thing we noticed was that the cruise decided it wasn't going to work - just randomly out of the blue the cruise part just stopped working. Every other function of the cruise worked - like the speed limiter but the actual holding the speed at 70mph for example just would not work.
The following day - hey presto - working again! And haven't had issues since!!

Then I had a brief issue with the electronic key fob where it wouldn't open or close the car, it wasn't the key itself because my other (spare) one wouldn't open or close it either. A couple of times i would have to get into the car via the key post and then the key would start the car without an issue.

Ok - all of those things were electrical right? But they ALL were transient and only happened once or twice and then were fine. I did have it put on a Star and nothing to do with electrics showed up!

Then, about a week ago, I was parked up in a car park - the key fob had been messing around during the day, but I had persevered with it and managed to get it to work after standing there like a muppet pressing the button multiple times. Anyway - was sitting parked up - ignition was on the dash lights but the engine wasn't on, I had the radio on, I had been on the phone and the lights were probably on for a while - for a max of 15 minutes. I got a warning come up on the command saying words to the effect of "your command doesn't have sufficient power and will shut itself off after 3 minutes" so I went to turn the car over and there was nothing. Sat there trying it over and over - just nothing at all - no noise whatsoever. So I call the RAC. As I'm waiting for them to come, it suddenly decides it's going to come back.
So I take it up the motorway and assume that I have managed somehow to drain the battery a bit.

Since then, the car has been rough to start on cold mornings it kind of turns over but does it slowly, far slower than usual. And the key fob has been messing around again today

SOOOOOOOO my question is; is it likely to be the battery OR the alternator??

I am SO poor at the mo that I can't afford to pay out for a new battery if it's not the problem and a month down the line I end up with having to have a new alternator. So do you guys think it sounds likely that it's the battery?

I know you can't tell for sure - but advice would be really helpful.

Also - does anyone have a Star locally (I live close to Rochester in Kent) that I could put it on? Would putting it on the Star actually diagnose the problem though??

My indy has moved to the Isle of Man recently and so I no longer have a local person to do things like diagnostics He was brilliant too - he use to just stick it on there for nothing and just charge me for the work.....I really miss him actually!

 

[tagnut]

Sounds like your battery but it could be either (or both) if alternator isn't providing enough charge. It's an easy five minute job to get both tested. Alternator should output 14.4V when car is running. Battery needs checking with a battery tester as you need to check cranking ability and whether it can hold a charge.

How old is the battery?

 

[jadefox]

Battery is from new - so 4 years old I guess. Car has done 120K miles tho - so it's had a lot of use.

And I have just been quoted for putting it on a Star machine in my local garage (not MB) - they want £60+ vat just to do that

What bothers me is that when it all started, I got my Indy to do it and he said there were no faults - so how can I even know it'll show anything....I so wish I knew someone else who would be willing to do it and then fix the poxy car one way or another.

Ugh and ugh. Oh and UGH!

 

[tagnut]

You don't need Star to do a battery test, any garage should have a battery tester and charge you no more than a few quid to check your battery and alternator

 

[jadefox]

Oooh ok - will look into that then, thank you! Will let you know how I get on.

 

[219]

Could also be something like a defective earth strap failing to complete the circuit and going intermittently loose .

The car needs to be looked at by a competent auto-electrician before spending money on things that are not at fault .

 

[BaldGuy]

PM Bruce Millar JF... He uses a good indie in the Kent area....

 

[Mr Jadefox]

Update on the issue. My wife went to the garage and had the battery and alternator tested and they were fine, so probably just the odd electrical gremlin. :/

 

[BlackC55]

There will ba a date stamp on one of the battery terminals. A battery that is 5+ years old and is suspect it is best to change it IMO. Some battery testers are not very good at picking up a bad cell.

 

[grumps]

Get the eis (ign switch) checked out not an uncommon problem but difficult to diagnose

 

[Danny DeVito]

Sounds like your battery needs changing. The thing with sitting with lights on and the radio will very quickly suck the life out of an old battery. It's not toooo old so if left for a while it will return to some sort of life, enough to carry on as normal. It will also perform badly when cold like slow turn over. I'd ignore the battery test and replace when you save up enough. The other issues may or may not be related but will ( most of them) sort themselves out. Randomly my fob doesn't work but i don't think it is battery related. Stick a new battery in and you will straight away hear the difference in turnover. Also dont sit with the lights on and radio etc without the car started.

 

[Danny DeVito]

Hey Olly, SHOUT its monday

 

[jadefox]

OK, Danny, that does makes sense.
The fact is, I've been saying since this whole situation started that I think it's the battery - trouble is I keep getting told differing things.

Right - an update: after on Monday, getting told it was absolutely not the battery - because the garage tested it and the alternator and it seemed to be charging fine and up to its voltage, tonight I had been driving it around a few places and then stopped at the school to pick the kids up - got back in, went to fire it up - nothing
So I give it a few minutes, try again...nothing, this goes on for a few attempts till I accept that it's not going to work.
Now bare in mind I've been told its absolutely not the battery, I call the recovery people, he comes out - after I wait an hour with bored kids
He puts a meter on it, it's showing that it's totally flat - it says on the meter - change battery.
I tell him i've had the poxy thing tested on Monday by a garage and they've said it's fine, he shrugs, puts the jump leads on and it fires back into life.

So I have now dropped it off at a garage and told the guy I want it sorted.

I wish the car would just WORK!!!!!!!!!!!

 

[Howard]

He jump started it ?

From what , the van or a booster pack ?

 

[jadefox]

I wasn't looking tbh - I think from a booster

 

[Howard]

Did he put your lights on before he connected it up ?

Lots of sensitive electronics can get spiked by jump starting which is why MB don't recommend it.

If you put a consumer on ( lights for example ) before connecting up , you take the spike out of it.

 

[Danny DeVito]

Did he put your lights on before he connected it up ?

Lots of sensitive electronics can get spiked by jump starting which is why MB don't recommend it.

If you put a consumer on ( lights for example ) before connecting up , you take the spike out of it.

Does that mean that everytime MB replace a battery they turn the lights on first ? I thought electronics were supposed to be getting better not worse. Years ago you could drop a spanner across the poles and now if you try and jump it the equipment gets buggered. And wouldn't you think that they could just throw in a shunt or a few caps to take any spike off ? I'm sure a few quid would sort it during production. Anyway rant over and about the battery.
Did the garage do a discharge test or just stick a meter on it ? A meter will of course read full power if you drive it in. The discharge test may show more but maybe not. And of course i doubt your alternator has any problem. I'd say 50 quids would sort you with the battery. And happy days are here again..:bannana::bannana:

 

[jadefox]

Sadly Danny, no such luck

Its been with a mechanic (an MB technician) for three days. He first tested the battery and it was dead as a dodos doodah.
He then charged it back up and then put it in the car and tested the voltage, turns out there is a draw on the battery continually, even when the engine is off. His best guess at this point is a faulty sensor - he said that he also noticed that the dash was not turning itself off after the key was taken out for about 10 minutes (something i hadn't noticed before but I don't tend to sit in it after I've stopped the car) and so he feels it's definitely a control sensor which has gone (I think he may have said the A sensor or something?)
However, when he disconnected it, then re connected it the sensor started working fine. This could I suppose account for the intermittent problems I've been having on and off - and the fact that it's not the first time the car has just not wanted to start.

Anyway - he wants to be certain that he is right so is keeping it for another few days to see what it does. He has also informed me that if it is this sensor then it's likely to cost about £500, PLUS it needs a new battery because this one is damaged AND I also have another issue with my wing mirror indicator light (broken wire) which is going to need fixing prior to my MOT which will cost another £200

I am not a happy bunny.

 

[Howard]

Does that mean that everytime MB replace a battery they turn the lights on first ? I thought electronics were supposed to be getting better not worse. Years ago you could drop a spanner across the poles and now if you try and jump it the equipment gets buggered. And wouldn't you think that they could just throw in a shunt or a few caps to take any spike off ? I'm sure a few quid would sort it during production. Anyway rant over and about the battery.
Did the garage do a discharge test or just stick a meter on it ? A meter will of course read full power if you drive it in. The discharge test may show more but maybe not. And of course i doubt your alternator has any problem. I'd say 50 quids would sort you with the battery. And happy days are here again..:bannana::bannana:

I don't know Daniel ....

Just passing on info that various indies and MB techs have given me over the years....

The SAM's are sensitive to spikes , maybe the old vitos aren't as they aren't that advanced , i don't know , but i was just trying to help.

Obviously , you know better. Thank you for informing me.

 

[Dieselman]

It looks like the front SAM may be playing up keeping some circuits live after switch off.
How can a repair to a mirror wire cost £200?