'02 SL500: Dead. No electrics

[Chucklehead]

Hi all,

I'm trying to start my late father in law's SL500. It's in a bit of a sorry state, and I'm trying to get it over to my place to tidy it up a bit and sell it on.

The battery up front is fully charged, but there's no power to anything. I had to use the blade key to get in to the car, but absolutely nothing works: horn, hazards, boot release.. I tried to open the boot with the blade key but the barrel just spins.

I had hoped I could get in to the boot to check the state of the battery in there and charge/replace as required. If that battery was completely dead, is there no amount of charge in the battery up front that will allow anything to function?

What are my next steps?

 

[LostKiwi]

Start the engine. It uses the front battery. Allow to run for a few minutes then try the boot release. You may need 1/2 hour or more but eventually it should allow access to the boot.

The way these are set up the front battery is for essential items required to run the engine only. The rest of the car runs from the rear battery.

 

[Chucklehead]

Hmm. With a fully charged battery up front, it's not starting. Doesn't even acknowledge there's a key there, so that's more concerning.

I have got in to the boot now via the 3rd brake light, and the battery is dead as a post, but it also has a rounded nut, so that has stopped okay until daylight tomorrow.

 

[ajlsl600]

Yr lookin at 2 Batts then methinks. Go varta, front starts motor back runs all consumers. Likely a lot of issues resolved after. Maybe you get all faults listed then deleted these cars can generate 3 pages of faults all linked. To low voltage.

 

[Craiglxviii]

It’s quite likely that there are so many undervoltage errors, they’re causing other cascade errors of their own.

The key to this one will be getting the cranking battery charged. Does the key turn in the ignition lock?

 

[Chucklehead]

Nope, nothing. It's literally like there's no battery in the car at all.

 

[flowrider]

Fully charge both batteries and check all the fuses.

 

[Chucklehead]

Thanks all. Two new batteries and I got it running.. unfortunately I'm getting a red battery icon which I'm assuming is a consumer battery fault of some sort. It's getting 14v, so I don't know what the issue is. I'll search round the forum for things to try.

 

[ajlsl600]

You changed both battery ?

 

[ajlsl600]

Did you clear all the faults? I recall a similar thing with my vdoz wheni changed mine.

 

[Chucklehead]

Both batteries have been changed. Is there a basic reader/diagnostic I could get to reset? Assuming that's what is required..

 

[Botus]

they are fussy and need almost dealer spec diagnostics kit to talk to enough of the car that's having a moment.

where's the car. You might have someone nearby that can plug their's in and give it a kick. or you'll need a 100 to 200 quid bit of kit on something like this to make sensible progress.

As you're not keeping it I'd get a generic one that does decent amount of modules and talks to most other brands.... I'd see how cheap you can get the autel MOT pro... now a run out model, but talks to more on a S500 than £2500 quid Snap On gear (not on injector coding, but for reading and clearing its better). Some have on the internet for 200 quid which is an utter steal (wow Sealy branded ones for 500 to 715 on ebay !!). But it only does BM and Merc 2012 or earlier. Ford, Honda, Hyundai Toyota VAG and many other it does 2018 or earlier. But you need to get the last updates... so tread carefully or you'll get a grey import one that does almost nothing and doesn't update

their later one… can't vouch for what it does but the spec / features read well https://www.ebay.co.uk/itm/ALLSyste...836979?hash=item1f10eb3833:g:Q2MAAOSwsQJe1f0X

 

[Chucklehead]

I'm just outside Glasgow.. the positive cable on the battery is looking rough, so I'll replace that and then start again. The rest of the car is a bit rough round the edges with various issues, so it'll probably be a case of getting it running and selling it as a project.

 

[Botus]

damp under the front carpets causes corrosion on the terminals of the multiplugs on lots of modules hidden there, it causes multitudes of fault codes - acf50 and lots of remaking of connections to clean pins up ….before people knew about this main dealers would have the car 6 months and have a 5k bill waiting and still it wasn't right