Fuel Level Sending Unit
Thread Starter
Member
Joined: Aug 2005
Posts: 145
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From: Ohio
1992 400E
Fuel Level Sending Unit
My gas gauge has been acting funny recently. The low fuel light that is supposed to come on when I am low on fuel does not do so. I know the actual light bulb works though, since it comes on when I turn the key in the ignition. Also, When I get below 1/4 tank, the needle starts to fluctuate wildly. Is this my fuel sending unit, or is it something else?
It kind of scares me when I'm not really sure how much gas I have left...
It kind of scares me when I'm not really sure how much gas I have left...
MBWorld Fanatic!
Joined: Apr 2005
Posts: 1,594
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Mercedes-Benz w124
same thing happens to me... but not about the light. the needle just randomly flickers. What i have noticed is that the highest point of the needle is how much gas i have.. any idea to fix it? i remember reading a long time ago, that to fix it, i would need to ground some wire in the trunk or something....
Thread Starter
Member
Joined: Aug 2005
Posts: 145
Likes: 0
From: Ohio
1992 400E
I did some searching, and while not much came up on this site, there was some info I found in other places. The problem I have is caused by a faulty sending unit, and/or a loose ground. The ground is located in the trunk on the driver's side, near the antenna. I'll check it out, hopefully I just have a loose ground.
Newbie
Joined: Aug 2005
Posts: 16
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From: New York
'87 300E
Bad sending unit?
Please keep us updated on your resolution. I had the same problem. I cleaned the grounding wire which did not help in my case (brown wire near the antenna). I then replaced the sending unit in the fuel tank. All was fine for a while. Now the fuel gauge only works correctly until fuel level goes down to 1/2, then it gets stuck. Is my new sending unit faulty? Any suggestions would be greatly appreciated.
Thanks,
-Andy
Thanks,
-Andy
Newbie
Joined: Feb 2004
Posts: 22
Likes: 0
From: ISRAEL
300TE
Bad sending unit
I had the same problem and it was the sending unit.
i took it out opend it. there are 3 tense's wires.
2 for the float to indicate the fuel level for the meter, and one for
the the lamp.
at my sending unit one of the wires (the level wire) was cut.
i took a soldring iron and a small pincette and solder the wire to it place.
its a 20 min. job. its about 4 month's working great likE a new one.
To check the fuel meter
1) take out the connector from the fuel sender. - at acc. meter should be
at zereo point
2) take a short wire and short the positive common wire (check the positive
wire with a voltmeter with one end of the probs to the ground, it should be
12v , acc on)
to one of the two pins on the sending unit connector. if it is the lamp wire
then the lamp at your fuel meter will light.
place the wire to other pin of the connector the fuel meter should jump
to max.
GOOD LUCK!
i took it out opend it. there are 3 tense's wires.
2 for the float to indicate the fuel level for the meter, and one for
the the lamp.
at my sending unit one of the wires (the level wire) was cut.
i took a soldring iron and a small pincette and solder the wire to it place.
its a 20 min. job. its about 4 month's working great likE a new one.
To check the fuel meter
1) take out the connector from the fuel sender. - at acc. meter should be
at zereo point
2) take a short wire and short the positive common wire (check the positive
wire with a voltmeter with one end of the probs to the ground, it should be
12v , acc on)
to one of the two pins on the sending unit connector. if it is the lamp wire
then the lamp at your fuel meter will light.
place the wire to other pin of the connector the fuel meter should jump
to max.
GOOD LUCK!
