[agentu008]

I have a i30 - 2016 with a heated steering wheel.  Today I pushed the button a few times and nothing happened. After a few minutes I pressed it again and it worked.

Are there any specific conditions that hate to be met for the heater to start?

[agentu008]

Now it wont go off.... When I press the button it lights up  a little more but when I let go it doesnt go off. I pulled the fuse... it went off.... I put the fuse back... its on again

[The Gonz]

I'd be homing in on that switch. I've never seen one. Do you have a picture?

[Shambles]

Spooky, this.

My HSW switch is also playing up (Ioniq) and feels sticky when pressed - and it's slow to rise. I put it down to the sheer amount of tea/coffee/milk it's been exposed to over the past 4 years.

So I agree - get the switch investigated as the easy start option.

[agentu008]

This is the button panel. Other buttons work good. If I press the HSW button 100 times doesnt work, then all of a sudden it works for another 100 times and so on. It doesnt seem to be related to anything else in the car...

[The Gonz]

In the absence of a schematic, I'd:
1. remove and disconnect the button panel
2. locate the connector pins that correspond with the function of the HSW switch
3. confirm that the switch is making a connection between the pins when pressed
4. if this looks good, investigate any looseness in the connector or cabling
5. if not making a reliable connection, consider pulling the switch panel apart or replacing it

[agentu008]

Update:
Found the trick! When it stops working if i turn the wheel more than a full turn the button works again and keeps working no matter the steering wheel position and. Then after no specified amount of time it stops working until another wheel turn.  But when it works it works every push, no matter the wheel position, with engine on or off...

[The Gonz]

Good, so it looks like you successfully jumped step 4. Wheel movement is likely to be associated with looseness in cable and/or connectors near the wheel movement area, not the switch.