Make use of that warranty while you have it. Nicer weather is on its way, and I'd say sacrifice the time now while under warranty rather than time and money down the road.
May be something so small you can see it or something in the 4WD switch or in the dash.
In either case wiring/electrical problems are sometimes the hardest to track down.
Try to take note of ANYTHING that you touch ,see,hear, when it blows. May help you to find the cause.