jimsinessex
Senior Member
- Joined
- Aug 4, 2003
- Messages
- 350
- Reaction score
- 1
- Location
- Essex
- Your Mercedes
- 2008 W209 CLK 320CDI Coupe
Thought my recent experience might be useful to W208 and W202 owners.
Driving home late at night I lost practically all the electrics progressively over a period of about 30 mins driving. First sign was a slight dimming of panel lights, later followed by ABS, ASR and SRS fail warnings. No charger fail warning was received. Got to destination with just about only the engine still working. Battery volts were 12V shut down, 10V with engine running.
Cause was found to be a broken main alternator output wire. The charge fail alarm is supplied via a separate wire and was still seeing full alternator output so no warning. Luckily the undertray beneath the alternator was plastic as if either broken end had touched metal the display of sparks would have been spectacular and possibly catastrophic. One end would have been a dead short across the battery, the other would have earthed the full output of the alternator.
It may be worth checking this wire for tightness or distress next time W202 and W208 owners have the engine undertray removed.
If panel lights seem dimmer than they should be then check the battery volts with engine running pronto.
Jim
Driving home late at night I lost practically all the electrics progressively over a period of about 30 mins driving. First sign was a slight dimming of panel lights, later followed by ABS, ASR and SRS fail warnings. No charger fail warning was received. Got to destination with just about only the engine still working. Battery volts were 12V shut down, 10V with engine running.
Cause was found to be a broken main alternator output wire. The charge fail alarm is supplied via a separate wire and was still seeing full alternator output so no warning. Luckily the undertray beneath the alternator was plastic as if either broken end had touched metal the display of sparks would have been spectacular and possibly catastrophic. One end would have been a dead short across the battery, the other would have earthed the full output of the alternator.
It may be worth checking this wire for tightness or distress next time W202 and W208 owners have the engine undertray removed.
If panel lights seem dimmer than they should be then check the battery volts with engine running pronto.
Jim
