Lately while im driving I will sporadically see my reserve fuel light start to flash for a couple minutes without any kind of message coming up on the display to explain it. I have searched thru the manuals multiple times and cant seem to find any info on the reason for this. This happens when my fuel is above a quarter tank to full so the reserve is not being used whenever this happens which makes it even more puzzling. Anyone know?

Also I get the "lamp defective" message every time I use the car ( with lamps turned on or off ) but I cant find any defective light, they all seem to be working. Is this by any chance related to my issue? is it some sort of gauge cluster malfunction? I only have 85k miles on my car so these types of issues seem odd.

 

Can't help with the first issue, but may be able to help with the "lamp malfunction". Although lamp defective tells you have a lamp out, only certain actions trigger it. This malfunction is reset every time you turn your car off. Start the car with lights off and foot off the brake. There should be no malfunction. If there is, go no further. You need to get your car scanned to find the problem. If no malfunction, press the brake pedal. If the lamp defective comes up it is one of your brake lamps. If no malfunction put the car in reverse. If the lamp defective comes up, it is a reverse lamp. If no malfunction, turn the headlamp switch to the first position. If the malfunction comes up it is a city lamp, side marker, tail lamp or license plate lamp. No malfunction turn to position 2. If you get the lamp defective it is a headlamp. Do the same for the turn signals, high beams, and fog lamps front and rear. Takes a little detective work sometimes to find the lamp causing the error. This system is very sensitive to voltage. A lamp may be working, but on its way out. Following the above steps will tell you where the problem lamp is.

 

It could be that your fuel cap is not closed properly. try installing a new fuel cap, very inexpensive item from autozone or advance auto parts.

 

Thank you both for your help. You would assume that if they built in a flashing light then there would be some official documentation in the manual or elsewhere as to why it does that.

 

From 1998 E320 manual (page 95):

Fuel Reserve and Fuel Cap
Placement Warning

When the warning lamp comes on and the symbol appears after starting the
engine, or if they come on while driving, it indicates that the fuel level is
down to the reserve quantity of approximately: 2.1 gal (8 liters).
The warning lamp blinks when the fuel cap is not closed, or a fuel system leak has been detected. Retighten cap and see if lamp goes out. If the warning lamp continues to blink after closing the fuel cap correctly, have the fuel system checked at your authorized Mercedes-Benz dealer as soon as possible. Leaving the engine running and the fuel cap open can cause the "Check Engine" lamp to illuminate.

FYI - A bad gas cap seal can cause the light to blink. Cheaper than a gas cap.

 

Thanks RichM. Good info on finding the malfunction.


Rock

 

"Lately while im driving I will sporadically see my reserve fuel light start to flash for a couple minutes without any kind of message coming up on the display to explain it. I have searched thru the manuals multiple times and cant seem to find any info on the reason for this. This happens when my fuel is above a quarter tank to full so the reserve is not being used whenever this happens which makes it even more puzzling. Anyone know?"

Sounds like you have an intermittant short in the fuel level sensor---you may want to pull the trunk covering back and inspect the sensor connection---if good then at some point you will have to replace the fuel level sensor!!