Yet more Electrical gremlins - PeachParts Mercedes-Benz Forum

stcbenz83 · #1 02-24-2007, 10:10 PM

I don't even know why i bother to keep my 240 in storage. I end up using it for a couple days a month anyways when the 300D breaks down

So the past 2 days the warning lights on the left side of the dash (break pad wear sensor, battery light, and some other light) were not illuminating during my glow cycle. Since the Battery light wasn't illuminating while i was driving, i thought mostly all was well.

NOPE! today on my lunch break, i got out to start my car to get some lunch. It started very odd, like it turned over slow at first, then fired up. So me being slightly retarded decided "wow, i better try that start agian". so i turned the car off and sure enough the battery was drained.

I had to have my car jumped to get it home, came home on my lunch break, switched cars and im leaving the car like that until i can get around to fixing it (or my father fixes it

) Which sucks because today and tomorrow is a big ice storm.

So this is the 3rd time this winter that the 300D has been INOP to the point were it cant be driven. I have no clue what this problem could be. The alternator light isn't illuminated, plus the alternator is brand new. But for some reason either the battery isnt getting a charge, or the alternator isnt charging Because when i was driving it home, i could either have the heat on or the radio on, but as soon as i hit the heat button, the radio went off agian. Im at a loss here. COuld this just be a bad battery? a fuse perhaps? any suggestions would be great, since time is really limited.

THANKS!

winmutt · #2 02-24-2007, 11:33 PM

Open ground circuit ? Do the gauge all work?

stcbenz83 · #3 02-25-2007, 12:15 AM

Yup, all Gauges are working fine... well except the clock, but what else is new

just the left side dash lights do not come on. thats about the only thing wrong with the dash

Jeremy5848 · #4 02-25-2007, 12:59 AM

Two possible causes:

a) Alternator not charging well -- most probably cause is worn brushes, part of the regulator, a separably replaceable part, fortunately. That would explain the idiot lights, the weak battery, the starting problem.

b) Battery is nearly gone, isn't holding a charge as well as it should. Doesn't explain the problem with the idiot lights since with the engine running, a good alternator should keep the voltage at almost 14 Volts.

Jeremy

FineOlBenz · #5 02-25-2007, 07:41 AM

I had the same thing on my 240. The charging system is not working. There is no fuse for the altenator unless there is a fusable link. Easy fix try replacing the brushes/regulator. It's much easier than the alternater. Simply disconnect the battery of couse, and remove two screws that hold in the brushes from the back of the alternater. Replace in reverse order (I copied that from the Childrens Manual

). No contact from the brushes cannot turn on the charging system or the warning lamp. I know that's dumb but that' how mine ended up.

stcbenz83 · #6 02-25-2007, 10:32 AM

The alternator is less than 2 months old i'd say. It went out earlier this winter on me already.

99E300TD · #7 02-25-2007, 10:44 AM

Even "new" alternators can be bad - especially if you got a rebuilt one that was done half-assed. Back when I used to do some of my own work - I took a couple to a local Bosch repair shop - they rebuilt them for about $60 each back then (maybe 10 years ago) but did great work. I would have to imagine the early failure rate for the "cheapie rebuilds" at the local parts store would be pretty high. Might be worth checking out...

Stevo · #8 02-25-2007, 10:48 AM

Check with your volt meter to see that you have at least 14 volts going into your battery at a fast idle, if so have your battery checked at your local tire and battery shop. How old is it?

stcbenz83 · #9 02-25-2007, 11:31 AM

battery came with the car. It dosn't appear to be that old. But i must admit that i have done my fair share of running it dead and charging it. (mainly from changing the fuel filters and have a primper pump that leaks more fuel than it pumps). I think ill go to the auto store and have my battery checked and she if thats the problem. I hope its not the alternator. It was a real PITA to change.

stcbenz83 · #10 02-25-2007, 11:16 PM

anyone?

1ajs · #11 02-25-2007, 11:28 PM

could it be a ****ed cable somwere? you know how cables like to rot eh?

pick up a cheapy batter you can use to do a test with you could set up as a back up power source for the laptop and router if the power goes out

so ya got somthing to do

chiwanga · #12 02-25-2007, 11:34 PM

here is the test for the alternator: start the car, turn on the headlights, then while the car is running, unplug the negative terminal on the battery. If the lights stay on, your alternator is doing its job, if not then, its not. This will tell you if its your alternator, or battery.

stcbenz83 · #13 02-27-2007, 04:58 PM

Quote:

Originally Posted by chiwanga

here is the test for the alternator: start the car, turn on the headlights, then while the car is running, unplug the negative terminal on the battery. If the lights stay on, your alternator is doing its job, if not then, its not. This will tell you if its your alternator, or battery.

yup, Bad alternator. But how come? I just replaced it litterally like a month and a half ago.

chiwanga · #14 02-27-2007, 08:57 PM

Some cheap rebuilds dont replace the regulator. I have seen it before.