disaster but was so close to home

[123sean]

hi went out to pick up an ebay item in middle of nowhere thursday evening and on way back noticed my lcd display in bottom of dash [2002 c240] was going dim ,thought nothing of it, stopped at traffic lights all ok pulled away and display turned red ..... lights went out [was in auto setting ] so manually turned lights on ,steering felt heavy and just made it home ..
,found out it had threw my alternator belt , got a spare and was going to fit today but checking faithful' you tube' for serpentine belt routing noticed they were fitting tensioner and idler so checked both and found tensioner bearing shot ...... so back to computer and ordered idler and tensioner . now got to wait for parcels maybe before xmas .hoho ,,
query , why did lights go out in auto setting ....??

 

[artyman]

You get some funny stuff happening if the battery is low, which it probably was if the alternator belt had gone.

 

[carat 3.6]

The car will turn the lights off to try to save battery power.

 

[markjay]

The car will turn the lights off to try to save battery power.

Or - I'm guessing - maybe the light sensor didn't work properly due to low voltage?

 

[carat 3.6]

Yes, could be that to. If it is trying to save power it will normally give a dash warning like “Battery protection: Convenience functions temporary unavailable”.

 

[Spider10]

In my jag xfs ( i know its not a merc) my battery failed over night i went to start it started fine no warning lights, but no power steering so did some digging after e few in polite words and its apparently the 1st system the car shuts down changed battery all sorted no issues