The gauge on my 79 SD flips from 1/2 full to empty, as well as no reading at all at times, this all seems to occur if the tank is under 1/2 full, any ideas?

Pull the probe from the tank and clean the contacts and resistance wires--VERY CAREFULLY!

That could work but probably won't. Best bet would just be a new fuel level sender.

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1983 Mercedes-Benz 240D
Automatic, A/C, Power Sunroof, Power Right Side Mirror
231K Miles FOR SALE MAKE OFFER

I had one that bounced, changed it with a used one, Not it just reads at 1/2, moves a little, but ran out of fuel the other day.
Do not know how much a new ones is, or if I now have a wiring issue?

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83 300SD Dark Silver Dark brown inside

Mine does fine until i get down to 1/2 a tank, then it starts bouncing and goes way below the empty mark.

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1983 240 D-SOLD
1979 300SD

Check your ground wires to the cluster.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

mine does the exact same thing but still have not got around to fixing it. It could be a ground issue with the instrument panel however not very likely. And that sending unit could be dirty which is most likely the reason.

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http://i148.photobucket.com/albums/s...titled-1-3.jpg
1981 300d

If the sending unit was dirty wouldn’t the gauge just be “stuck”?

I guess you could have a loose wire in the sending unit…

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

Where Is The Fuel Level Sending Unit Located, As Well As The Ground On The Cluster?

In the W123 the fuel level sender is under the first aid kit, and the ground *should be* a brown wire in the cluster.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

right on ,thank you, will post how repair goes.

I found a sure fire way to find out if it is the ground, I was having problems with both fuel and temp being all over the place, If i hit the dash they would go back to normal. pulled cluster cleaned contacts I was good to go.

Does this work at all like the oil level light where there is an electronic buffer that desensitizes the system to sudden changes?

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