advice needed: traction light on full time

1. Is your car working well now, without any current issues?
2. The brake fluid level in the 3G reservoir will vary substantially, depending upon whether the brake actuator pump recently operated. After the pump has recently run, the level will drop. If you leave the car for a while with the hood open, then after you return in a few hours you will find the level has risen back up. At that point, the level should be at the top mark in the reservoir if the brake pads are new.
3. This issue of varying brake fluid level is especially pronounced with 3G. I haven't noticed that as much with Classic and 2G.

 

Well, I do not know if an excessive brake fluid level would lead to the brakes dragging or not. Nevertheless if your car is good now, that is what counts.

 

If the car's been sitting and you get in thru passenger side, reach over and release the hood latch, without opening driver's door, you DON'T activate brake pump, you should see fluid level at or near MAX (assuming pads near new):



If you then open and close driver's door the pump activates and over course of 10 seconds or so the level drops, to be like this:



So if you checked via first method and level was above max, that being the "highest" case, you should be ok removing some, bringing it down to max. If your pads are partially worn it's still a bit too high, you mainly need to keep in mind to remove a bit more while putting on new pads.