mercedes 300e trouble with gas guage
 

I own a 1988 Mercedes 300e and the gas gauge has been moving up and down giving me different readings on the amount of fuel. Sometimes the light comes on and then turns off. Its difficult to know how much fuel is left. Doesn anyone know how to fix or repair the prolem. Thank you

the fuel sender unit is the common culprit. It isn't always a faulty unit - it sometimes is just a bad connection.

Does the needle go all the way to E and then back to the approximate tank vol (and/or sometimes swing all over the place)?

I would guess either the connection is bad or the sender unit is bad...

Fuel guage
 

Trimi,

You need a fuel level sending unit.

Install from trunk after removing panel behing back seat; you will find instructions on this site. Pretty easy diy project. Get the gasket when you order the sending unit also.

i have a new in the tube fuel level sender. i never got around to installing it on my '92 300e, car is gone but i still have it.

part # 124 542 00 04 it is a bosch part

i paid around 100.00 for it best i can remember.
price it and email or pm me.

peter

The gauge on my '91 124 reads fine above 1/2. Below that it becomes erratic. The light works fine, of course, since it is operated by a different signal on the sending unit.

I replaced the sending unit and it made NO DIFFERENCE. I also tried a different gauge and that made no difference either. I cleaned tightened every ground connection in the car that I could find. That made no difference either.

So, I guess there are ghosts in my electrical system.

YMMV

I have had this exact problem on my 300E and the 280E before it. Identical symptoms. I even contacted VDo about it. Replaced sender on both, didn't help. There was talk of a cold solder joint on the instrument cluster behind the fuel gauge that could fail over time, but I never got around to testing it.