My driver side heater vents sporadically will not provide heat.

What is your question?

Also when it does provide heat, sometimes when I adjust the temp to 60 degrees and then back up to 90 degrees, there is no hot air. The passenger side works fine ... and always heats and the temp can be adjusted. This happens in all sorts of outside temp ranges. When ever I took it in to get it fixed, they could not recreate the faulty heating so the repair tech guy said he manually set the programming to "fix" it. That lasted for about 6 months and is now not heating properly.