C180k Electrical Issue

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howard keeling

Active Member
Joined
Sep 18, 2017
Messages
77
Location
essex
Car
R170 SLK, W203 C180k Elegance, VW T2 Bay and a Lotus Elise
Driving along today the battery light appeared on the dash followed by the ABS light, I had the cruise control on at the time which disengaged and the car started to slow, 10 seconds later both lights disappeared, I reset the cruise control and all was good.
An hour later it did the same, only last 10 seconds or so and then back to normal.

The battery isn't flat as it spins the engine over really well and starts first time.

Would a duff battery do this or should I be looking else where.
 
Check that the battery terminals are clean and tight, if they are then you need to get the fault codes read via Star, although there may be no dash indication of faults the ECU will have stored something.
 
Check that the battery terminals are clean and tight, if they are then you need to get the fault codes read via Star, although there may be no dash indication of faults the ECU will have stored something.

Ta, will phone my usual garage tomorrow and find out if they have the gear to do it.
 
Ta, will phone my usual garage tomorrow and find out if they have the gear to do it.

If they are not an MB Specialist I doubt they will have Star system, generic fault code readers are not always able to interrogate the ECU at a deep enough level.

Good luck and let us know what happens.
 
Just checked the voltage level using the dash display, (found an old thread where some one had a similar issue), 12.5 volts with engine off, 14 volts engine running, I'll leave it displayed while driving and see what happens when the battery light next appears.
 
Just a quick update. Not managed to get the codes read yet as my indy doesn't have the right gear and merc main dealer too busy.
Have been driving it around with the charging voltage visible on the dash display. 11.9 volts before starting, drops to 10v while turning over returns back to 11.9 when running. It probably takes about a mile of driving before the voltage increases to 14.2 where it stays for all of the journey. On the odd occasion the abs light comes on and a message on the display. Can't remember exactly what the message is will note it down next time.

Does this sound like a failing alternator with an intermittent problem or something else. The battery doesn't appear to have the charge that it had a week ago.
 
Just a quick update. Not managed to get the codes read yet as my indy doesn't have the right gear and merc main dealer too busy.
Have been driving it around with the charging voltage visible on the dash display. 11.9 volts before starting, drops to 10v while turning over returns back to 11.9 when running. It probably takes about a mile of driving before the voltage increases to 14.2 where it stays for all of the journey. On the odd occasion the abs light comes on and a message on the display. Can't remember exactly what the message is will note it down next time.

Does this sound like a failing alternator with an intermittent problem or something else. The battery doesn't appear to have the charge that it had a week ago.
upload_2018-5-26_23-12-50.png
Could be this, how many miles on your car?

ALTERNATOR VOLTAGE REGULATOR and Brushes A 003 154 98 06
BOSCH F 00M 144 147
 
Got agree with Old Spanners it sure seems like an alternator issue, should get 14.5 ish volts once started.
I have a little display that plugs in to the cig lighter on my Jag, as it doesnt get a lot of use, really handy at 2-3 quid from ebay
 
Just over 100k. I've been hoping something would completely fail, at least that way I'd know for sure.
 
How easy are the alternators to remove. Anything useful tips to make getting it out an easier job.

Not had a look yet.
 
How easy are the alternators to remove. Anything useful tips to make getting it out an easier job.

Not had a look yet.
Not very!
This should give you some idea.
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Good luck.
 
Ta for that, just looks a bit fiddly.
 
Took a long journey in the car today and about an hour in the battery light appeared and every dash light illuminated (basically stating all of the electronic systems were off) flicked back through the dash display and the voltage was showing 19V, everything basically stopped working, no indicators, wipers, light etc. The engine was running fine so not sure what damage was being done but as I was on the M23 couldn't really stop straight away. Anyway, I took the nearest junction, slowed right down and the voltage returned to 14.2V and everything reset itself.

Didn't happen again for the next hour.

I can only assume the voltage regulator wasn't doing its job, the output was 19V and the protection systems stopped everything from frying.

I have one on order from the link above, will have the alternator out tomorrow if it ever stops raining.
 
Yeah you must have thought you were running a hybrid seeing that voltage, good that nothing seems to be fried!!
Where are you in essex could offer some help if close enough, I am an Engineer so have most tools Based in Thurrock?
 
I'm in Roydon.Thanks for the offer, don't plan to start until the VR arrives.
 
looks about an hour away if you hit any snags ping me, on here and will try to get over.
 
cheers for the offer.
 

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