I recently purchased a 79 450 SEL and something is draining the battery...I was told by a friend that it might be a resister problem. The battery is arcing out.....can anyone tell what might be causing this and how can I fix it? Thanks, John

The battery itself could be bad, the top could be dirty and a small current if flowing across the top or the alternator internals could be bad.

Check those first then remove each fuse and put your DMM across the contacts. Measure the current in each circuit.

Maybe your trunk light is on.

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Regards

Warren

Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor

Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL

ENTER > = (HP RPN)

Not part of the in-crowd since 1952.

Warren,

The battery is new.

Is there a resister that could cause battery drain....that's what I was told but that doesn't mean anything because the guy that told me this is a hobby type shade tree BMW mechanic......LOL

I had a drain in my Subaru last year. I finally got tired of jumping the thing. Measure your voltage across the pos and neg terminals after a charge. If you have a short somewhere you should see the voltage drop slowly.

I charged my battery fully and removed all the fuses in the fuse box. I attached the volt meter across the terminals and one by one inserted fuses. My dad watched as I got to my 4th fuse and the voltage started to drop. I left that fuse out as it wasn't worth tracking down the short. No more power door locks for me. No more dead battery either.

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'85 300SD (formerly california emissions)
'02 Jeep Grand Cherokee Limited
'04 VW Passat W8 (6spd manual) SOLD!!
'68/'69 Empi Imp body on '65 Beetle pan
'93 Ducati 900 SS
'79 Kawasaki KZ 650
'86 Kawasaki KX 250
'72 Triumph T100R
'70 Yamaha R5 Rat Bike

What do you mean "the battery is arcing out"? Do you see sparks somewhere?

Mike

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1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra

I'm LOL.

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I got too many cars!! Insurance eats me alive. Dave

78 Corvette Stingray - 3k
82 242 Turbo Volvo - Manual - 270k
86 300e 5 speed manual - 210k
87 420sel - 240k
89 560sl - 78k
91 420sel - 205k
91 560sel - 85k
94 GMC Suburban - 90k
97 Harley Davidson Heritage Softail - 25k
00 GMC Silverado 1 ton 30k

Sorry guys, the battery is just draining, not arcing out. My old lady neighbor that sold me the car told me that's what it was doing but it is not arcing....LOL. I finally got the car started after a very long charge and moved it to my garage.

Thanks for the tips on diagnosing the problem. After searching the net, it seems like one of the problems with Mercedes is battery drain. I found many topics on this problem.

Thanks again,

John