About two months ago the vents on the dash stopped blowing air at all so I started with the fuses and it did nothing. Then randomly about a week later the air started coming back through with no issues at all. This lasted up until today when I started my truck and once again no air coming out of any of the vents. Any idea what could be the cause of this? Thanks!

 

+It could be a bad blower motor resister, a bad blower motor or a faulty switch. Check them one at a time.

 

So I took off the cover under the dashboard that protects the blower motor and started looking around under there. I noticed that one of the wires is corroded (think its the wiring harness [has 7 different colored wires that run up to a box on the right side of the dash]) and I pushed on it. After that I started the truck back up and AC came back on so I thought I figured it out, but this afternoon it wasn't working once again after I started my truck. The wiring harness would have to be the problem right?

 

Try repairing the corroded wire by cutting out the bad piece and splicing another piece of wire in its place. Also look for other bad wires and loose connections.