My '98 V70 AWD, 50000 miles, has an odd electronic climate control problem. I noticed last summer that there was a tapping sound that seemed to come from the center vent area. I deduced that it was related to the passenger side temperature control sticking and seeking in small movements. Running it through the extremes of its range seems to help, at least for a while. Now, it's winter. After driving for about a half hour and everything warming up normally, the passenger side dash vents start to blow cool air, even though the driver's side vents are blowing room temp or slightly warmer air. This is with both sides at the same temp setting or even with the passenger side set two degrees warmer. To get the dash vents to warm up a bit, as well as the floor vent, I have to increase the temp several degrees beyond the left side setting. Clearly, something has become miscalibrated or non-functional. What's involved in fixing this? Dash removal? Simpler accesibility? I have a third party extended warranty and may want to put it to the test.

Doug