Brakes pedal goes to floor but plenty fluid and good pads

Hi Anton It would help to know what vehicle you have.
are you sure its the hand brake light and not the brake fluid level light? It may be they are using the same light for both.
I am assuming the brake pedal goes to the floor if you don't pump it? This is really an open question without knowing the history or seeing your vehicle. Things that may create this fault,
brake pedal spongy or goes to floor (1) Leak of fluid in system, air in system, Incorrectly adjusted brakes, Flexible brake hoses porous brake pressure applied hoses expand. Leaky wheel cylinder or calliper. Badly worn brake pads or brake shoes. Leaky brake booster (brake servo) You need to methodically go through each of these possible faults and rule each one out. Good luck

Check fluid level as well as bleeding the brakes to get rid of air in system.

fluid is by passing rubbers in master cylinder . replace unit. noise if you are running engine could be air leaking from faulty booster unit

you definitely need to bleed the breaks

How to Bleed your Brakes by Yourself

Probably going to be a bad Master cylinder.

It take a few full brake application for the brakes pads to adjust there self and check the brake fluid level. Top off as needed with DOT 3 and be safe.

This is normal and you need to keep pumping the brakes till they reset there self. Once the brake peddle have reset there self and is firm, check the brake fluid level again and add brake fluid if low. After brakes have reset there self, go for a test drive around the block and check the parking brakes. Good luck.

bad power booster

First look for obvious leaks under the vehicle, especially the inside area of each wheel... If you see fluid, you have either a blown cylinder seal or a bad line (check the rubber hoses to the front and back brakes too) Repair the offending part and bleed the air out of the system... (remember to clean pads or shoes if they have fluid on them)... If you see no hint of leakage anywhere, then suspect the master cylinder... if you remove the master cylinder, check and make sure that it didn't leak fluid into the brake booster diaphragm (Brake fluid will destroy the booster)... as in any repair when you open the system (lose fluid), you will need to bleed out the air to restore function... hope this helps...;-)

You need to replace the master cylinder. If all else is good and the petal goes to the floor, that's really about all it could be.