Maroun Faddoul

I successfully completed this mod, using a 1K 1/2 watt resistor. Have had it for around 1 year, only thing is that when its a hot day, the aux option isn't recognised. I spoke with Jaycar and they said that when the resistor gets too hot it stops working, and said to put a resistor with a higher wattage. I'm a bit hesitant to do it as I don't want to short the HU. Anybody know what to do in this situation?