Im not sure how to start describing the problem, but here it goes.

Recently i noticed that my battery light stays on even when the engine is off and the key is out, also the fuel gauge goes to 1 quarter and if i press the brake pedal the fuel gauge bounces to zero.

I tried pulling all of the fuses and pulling fuses 6 and 7 dimmed the battery light but did not turn it off

i blelieve Its a short somewhere in the brake light circuit, aux fan or ac blower fan.

Has anything like this happened to anyone before?
Where should i look for these circuits intersecting?

any help would be appreciated,
thanks

1987 300D 124.133

Check the ground cable between the engine and body. that was a problem I had.

What Car? list your fleet of cars in your signature, this way you won`t have to keep answering "What Car?"


Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Disconnect the alternator. See if the light goes away.

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Palangi

2004 C240 Wagon 203.261 Baby Benz
2008 ML320 CDI Highway Cruiser
2006 Toyota Prius, Saving the Planet @ 48 mpg
2000 F-150, Destroying the Planet @ 20 mpg



TRUMP .......... WHITEHOUSE
HILLARY .........JAILHOUSE
BERNIE .......... NUTHOUSE
0BAMA .......... OUTHOUSE

ok now it doesn't do anything when the key is out, and when the engine is running looks like its charging the battery.

the light does go away when i unplug the alternator, but the brake pedal still makes the dash go crazy, the fuel gauge jumps around almost in full sweep and the check light bulb light goes on

abs light also blinks sometimes without any kind of pattern, just like a loose wire

this car is possessed

Did you check the ground???


Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

I think there's an intermittent trace in the cluster ground on the PC board(s) that needs to be resoldered

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

As per Charmalu something to do with the ground.

ground cables are all good, that i found,

also i found out that when the car is on, and the battery is unplugged the idle raises to 1.1k

but i don't see how all this would be affected by the brake pedal

Disconnecting the battery while the car is running is not a good idea, good way to ruin your alternator.

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96 E300d

I am not sure what the alternator/voltage regulator setup is on your car. However, I had a similar symptom on one of my gasoline cars, I.e., battery light staying on when key removed from ignition. I pulled the alternator and had it tested.... The voltage regulator was built in to the alternator, in my case, btw. There was a fault in the unit, but I just can't recall exactly what it was... Or whether it was in the VR or the alternator. It was a simple fix.

The shop that fixed it knew exactly what the problem was from my description over the phone... And they cured the problem by replacing the faulty item.
Contact an automotive electric shop and tell them the symptoms. They see this stuff all day long.
Good luck and I hope this helps.

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[SIGPIC]
Tom
SE Connecticut
1975 W115 300D

visit my blog:
http://mercedesdieselrebuildingdiederich.blogspot.com/

Diode in alternator has shorted .. I just gone through this whole. thing. About 125.00 bucks and a l;ittle time and you will be back in busuiness. I found a reputable person to rebuild the one on my car so there was no question on fitting. Hope this helps.

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Joseph Blackwell
1985 300SD
1990 300 2.5 Turbo

thanks for everyones replys, i pulled the alternator and had it tested, it was failing a couple of tests, now the car seems to be fine with a backup alternator i had,

Is there anything that could have caused this? the brake pedal still makes the fuel twitch and the bulb check light is on all the time now

Have you bothered to check all your lights yet? That is what the bulb check light is for. When you press your brake pedal it will turn your brake lights on with will almost always cause a slight change in the voltage which in these cars is enough to make small changes in the way the gauges read which ... frankly... is kind of normal.

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1996 s10 zr2 with a 6.5 turbo diesel
1996 c2500 suburban with a 6.5 turbo diesel
1981 300sd with a turbo 617
Monte carlo figure 8 car

all of the light bulbs are good and the right wattage, i even cleaned the contacts

i guess ill have to trace the whole harness to find an intermittent short

It was the alternator being shorted, got the thing rebuilt and it works fine now, who who knew the alternator can make the car go insane

thanks everyone for help.