tonight i was driving back home and as soon as i turn mi lights on i got the undervoltage cunsumer defective i kept driving with this light and the the battery/ alternator visit workshop started to flash the mi light began to fail i checkd mi belt and battery conectors and everithing was fine any ideas?

 

What year car and model are you driving. I have never heard of the terms undervoltage consumer defective, or visit workshop to flash.

If your lights are dim when driving there are two possibilities, the headlights are old, my 79 headlights were yellow, replaced them with new bulbs and they are white, ditto, dash lights and shift booth light.

If your car is new, then it is either an alternator or battery problem. checking the connectors is a good thing to do, but get yourself a battery tester and see what the volts are with the engine off and the with it running. If you battery is not pumping out at least 12.5 volts running you got a bad battery. Not running 12V to 12.5V is OK.

 

mi car is a c230 2002 coupe and mi battery in new. the problem only hapends when i turn mi lights on

 

I had this happen with a 1989 260E. The battery was fine but the alternator was fried. I could boost the car and drive about 15 km before everything in the car failed, including the engine as I glided into a service bay for a replacement. One other MB I owned had this problem intermittently when sitting in traffic with the wipers on, radio, heater, rear window defroster etc which severly limits the ability of the alternator to keep the battery at a decent charge. Usually the car takes things into its own hands and temporarily shuts off the defroster by making the indicator light blink. I'd check the alternator first then the battery. Even new batteries can fail if they are not being properly charged or are not correct for the car.

 

thank you all i think is mi alternator i will have it check today, does some one where can a buy a cheep one?

 

This is probably a long shot but I have a 2002 c230 kompressor and I have been getting the "undervoltage consumer defective" message. Eventually it evolved into a "battery/alternator" warning.

I checked the battery and it was working fine and so then I checked the alternator and it was definitely not putting out the needed 14V or so to properly charge the battery. I replaced it with a new alternator. I checked the voltage after and it was 14V. I drove it around the block a few times and everything seemed to be functioning perfectly.

Later though, the "undervoltage" message came back and when I checked the alternator again, it was only putting out 10.9 V. Any ideas? I'm thinking perhaps there's a problem with the wiring..

 

had same problem 2 time.

1) check your voltage regulator

2)thereis a litle cable ( blue) that comes from the alternator to the to of the engine check this wire some times it get loose couse of the belts. thecable is located near the supercharger

 

I will check those two things, thanks for the tip. Do you think is it likely that the voltage regulator damaged the new alternator or was it an unhappy coincidence?

 

i`ts comun that when the voltage regulator is damage, the test will show you that the alternator is not working, maybe your old alnerator was not damage. there are place where you can check both things you should do it.

cheers

 

In case you care, here's an update. I ended up returning the dead alternator to the auto parts store. They ordered a new one for me but it was the wrong one...After losing confidence in their products/service, I went ahead and purchased a new alternator through the dealer. Everything seems to be working fine now. *victory dance*

Thanks for taking the time to answer my post, guys