URGENT CANT UNLOCK CAR c32

[SavMan]

Dont forget the basics, test that you have good voltage at the battery terminals when the car is running. I spent several attempts on my last E class trying to find a cuurrent loss and had measured strong voltage coming from the alternator.
Finally thought let me see what voltage the battery was getting while engine is running to compare with the altrenator output and it dropped almost 2.5 volts.
The battery earth lead was corroded where it bolts onto the chassis!

 

[Billy albert]

I will post readings tomorrow , If you wanna help interpret the readings that would be good

 

[Billy albert]

Can someone tell me how to use this multimeter which setting ect

 

[Dieselman]

DC volts set to maximum 20v for the main battery voltage checks.

 

[SavMan]

Black lead in COM
Red lead in VΩmA
Turn dial to V (Solid line above 3 dots) either 2, 2000m or 200m depending on your multimeter

 

[SavMan]

DM is probably right best to start on 20 and then work down if you want to look for smaller current draws to either 2, 2000m or 200m.

 

[Dieselman]

Don't do this...

[YOUTUBE]Ftc3EQGZowk[/YOUTUBE]

 

[Dieselman]

Good advice here, but don't talk like this...

[YOUTUBE]FybqNO7et0k[/YOUTUBE]

 

[SavMan]

Good advice here, but don't talk like this...

[YOUTUBE]FybqNO7et0k[/YOUTUBE]

He sounds perfectly normal to me , in fact I am sure I have heard him at Upton Park before

 

[Billy albert]

Shall I charge battery fully before I attempt this

 

[Dieselman]

It won't matter.

I like Savmans way of checking each circuit, by checking for very low voltage drop across each fuse. That's neat.

The first check should be battery voltage both static and under load, then charging voltage, then check overall current drain by pulling the terminal off as in the 2nd video.

 

[Billy albert]

Thanks fellas but I have whipped it off as was dark and will place on charge and try tomorrow with more light

Thanks

Bill

 

[Dieselman]

One last point. Make sure your meter isn't showing the little "battery" symbol, as it will read incorrectly if it is.

 

[Billy albert]

Ok so battery is 9.55 v ATM

 

[Dieselman]

Ok so battery is 9.55 v ATM

With no load on it? If so, that's very low and sounds like it may have a dead cell. Let it charge for a while then remove the filling plugs and look for fizzing electrolyte in a cell.

 

[Billy albert]

Off the car 9.55

 

[Billy albert]

It's a merc battery date 09/09/10 so prob out of warranty has a window to check acid level but can't tell , is it ok to pop the 2 covers ?

 

[Dieselman]

If you can get the covers off without them snapping then it's Ok to do so.

 

[Billy albert]

So if they're not fizzing it's goosed right ?

 

[Dieselman]

So if they're not fizzing it's goosed right ?

They will all bubble a bit when charging, but if one is bubbling a lot it's short circuit, so dead cell.

9.55v is very low for an unloaded battery. If it's 20% down and has six cells that makes me think one has gone down.