I have been having a problem with my Coolant Level light being illuminated for nearly a year now (SLK32 '03). I did run low on fluid at one point and after refilling, the dash warning did not go away. I thought I might have a bad sensor, so I replaced the coolant level sensor. That didn't fix it, so I tried filling up the washer fluid, and then replacing the washer level sensor. I considered that I might have the wrong fluid, so I bought mercedes fluid and did a coolant fluid drain and replace. None of these things have worked so far.

At this point I did a visual examination of the wires and fuses, which showed no obvious fault. I checked the plug for continuity, and it is indeed a closed circuit. The only thing I can think of is that the float is stuck in the down position. I can't seem to find a way to get at the float though. I loosened the tank and shook it around to no avail (a rubber mallet didnt help either).

When I unplug the coolant level sensor, the light remains illuminated and the washer level indicator does not illuminate.

Is there an easy way to un-stick the float, do I have to replace the coolant tank, or is there another common fault I can check for?

Thanks for the help! I'm excited to hopefully finally finish this fix.

__________________
Black '03 SLK32 AMG