my dyson v8 absolute just pulses and won't suck at all, what's wrong?

The motor pulsing is the automatic cut-out. You have a blockage.

1. Disconnect from the charger. Let the machine cool down. Don't touch the trigger.
2. Open the bin. Pull the bin release catch up over a trash can.
3. Check for blockages in the cyclones and at the tool or wand attachment point.
4. Remove the wand and cleaner head. Check both ends of the wand for obstructions.
5. Turn the cleaner head over. Check the brush bar and air inlet. Remove anything wrapped or stuck.

IF THAT DIDN'T WORK: The blockage could be deeper. Fully remove the bin. Pull back the red catch on the base, slide the bin down and pull it off. Check the inlet path on the main body.

HEADS UP: The machine won't function until the blockage is fully cleared. Never use it while checking for blockages.