alymo

hey, i just got 07 headlights installed , drove around for a few hours then i got an error message that said" undervoltage consumer defective" turned off the car and started again and the message was gone..i haven't driven it since but i'm worried about that what does that error mean?

FrankW

which 07 headlights??

raklert

I got that error message to but after i pump up my stereo system for hours. I think you battery is not charging right. Try driving your car around and see if the battery is charging if erro meassage come up again then something worng with your battery.

alymo

i'll post picsof the lights in a different thread..i was just thinking the light installation might have something to do with it, maybe they shorted the circuit or something

Saprissa

why start another thread... just post a pic of your 07 lights here...

alymo

sure i guess i could..ok here hey are 07 w203 headlights and 07 aventgarde grill

alymo

hey guys i posted an earlier thread and got no answers so i'll try again. i got an undervoltage error in my car once it then went away the next day it happened a few more times. i checked the voltage on the battery and it reads 12.3-12.4 volts. what should i do? is the battery a possibility or is it most likley the voltage regulator or the alternator? how would i know ? please help i need my car tomorrow and don't know what to do!

alymo

hey everyone i got an undervoltage error on my car a couple of days ago and the problem has been persistant..i checked the voltage at the battery in idle and it reads about 12.3V i increased rpm with no change in voltage.
what do you guys think is it the battery? or could it be the voltage regulator or alternator? also can anyone tell me where the voltage regulator is on the car and how to replace it? i'll take the battery off tomorrow and get it checked but if it checks out ok my next step will be to replace the voltage regulator since its cheap..if all fails i'll replace the alternator...oh my car is a 2001 c240 btw

thanks

sosh

Instead of throwing parts at it spend a few bucks and have it correctly diagnosed.

SUNILP

The best way to diagnose it is with a Midtronics battery tester. THe voltage regular is located inside the alternator behind the black plastic cap. At this point, your battery should be fine. Sounds like alternator or regulator.

vettdvr

If your voltage is 12.5 volts with the engine running and 12.5 volts with the engine off and headlights on,, you have no problem. However if you have less than 12 volts with the headlights on and engine running you have a alternator problem. I don't do individual parts replace on alternators, I replace the entire unit. So your best bet if you need an alternator is to shop for a replacement.

I use equipment that looks at all 3 legs of the alternator output (at a single post for the wave pulsation from the diodes) when I made a decision to replace. I can normally tell if it is diodes, regulator or alternator itself. But if you don't get the voltages above you probably just need a replacement. Jim

vettdvr

I agree here, that is the easiest way, but every time I go to MB dealer and throw a "few bucks" it is usually over $1000 for each throw of the bucks. Not a big deal to change an alternator and I always try to save a buck when I can. Jim

alymo

thanks..yeah i get 12.4V at all times whether the lights heater, wipers....are on or not its just a little less than the normal 14V...i'll take it to the dealer and see what they say. thanks for all the info guys

Racin_fool

with the car running you should be able to read about 14 volts at the battery. If the car is running and you only see 12.3-4 volts then I would suspect that your voltage regulator has taken a turn for the worse. You can get just the voltage regulator itself instead of the whole alternator, but I don't know what kind of mechanical experience or tools you have available.

C230 Sport Coup

Didn't you say this happened after doing some electrical work?
Go back to stock, and see if you still have a problem.

Otherwise, how old is the battery?
Maybe it's not charging?
If it's old, it can short and drag the whole system down, and cook other things too.

damaged

Voltage is not as important as amperage, it is probebly the voltage reguletor, but check the alternator output before changing anything.

SUNILP

this is why you get a midtronics test done.

sosh

Where did you get that from. Voltage and amperage are both quite important. Try to start your car with normal voltage and low amperage and see what happens. Electrical devices can also be damaged by running low amperage. Did you flunk electricity in school??

damaged

???Thats exactly the point i was making. I have seen plenty of cars with 12-13v at idle but only a few amps, hence no charging. The midronics tester while good, is not the only means to test the system. A quality charging system tester from snap-on, mac etc etc works just as well.
The midronics test if i remember correctly is done with the engine off, so only tests the battery not charging system.

SUNILP

the midtronics test is done while the engine is off and while cranking and while on with loads on. Snapon's microvat is also nice. MB uses midtronics as standard service equipment at all dealerships.

damaged

I use the snap-on microvat, nice tool, I had to many odd readings and problems with the midtronics tester at the dealer, mainly due to one or two testers being passed around (read dropped) by 40 mechanics.
The main reason the dealers use the midtronics is because MB require the printout from it for warrenty claims. Most tech's i know prefer the snap on tester. Just my $0.02 worth.

SUNILP

Very True also.

alymo

ok guys i was getting the undervoltage message for the last couple of days and my car finally died today right away i shut it off and called a tow truck and took it to the dealer. the dealer did their thing and told me it needs a new battery and regulator..which is fine and then the tech called me to the shop and said that all the SAMs are failing after he installed the new battery and now my signals, wipers, power seats, dome light, remote trunk, fuel gauge, temp display are all not working.. the guy is trying to blame it on the mercedes bodyshop who istalled my 07 headlights a few days ago although everything was working perfectly before i took it in even after the battery died all these things were still working, he also tried to tell me that it may be coincedence that everything failed at once right there at the dealer after they installed the bettery...yeah right...what should i do guys i feel like the dealer screwed up my car and wont admit it and i can't prove anything on him...please any previous experience or advice is appreciated

alymo

ok guys my car finally died today right away i shut it off and called a tow truck and took it to the dealer. the dealer did their thing and told me it needs a new battery and regulator..which is fine and then the tech called me to the shop and said that all the SAMs are failing after he installed the new battery and now my signals, wipers, power seats, dome light, remote trunk, fuel gauge, temp display are all not working.. the guy is trying to blame it on the mercedes bodyshop who istalled my 07 headlights a few days ago although everything was working perfectly before i took it in even after the battery died all these things were still working, he also tried to tell me that it may be coincedence that everything failed at once right there at the dealer after they installed the bettery...yeah right...what should i do guys i feel like the dealer screwed up my car and wont admit it and i can't prove anything on him...please any previous experience or advice is appreciated

slammer111

Sweet, another Vancouver guy. Which dealer did you bring it to?

The headlights should do nothing. Total BS. Maybe it's a coincidence? That is weird indeed.

Keep us posted.