Front vents stopped blowing air, but back vents work like normal?

The vehicle listed above is a 1500 5.3-liter Vortec Flex-Fuel engine.

Just in case you need it

Vin #
1GNFK16327J209389

My front vents stopped blowing air. When I turn on back vents, they all perform as they should.

1 year ago, my front vents stopped blowing air. It was going to be a few weeks before we were able to look into it so I had to use the rear vents for the kids.

I noticed while driving and using the rear vents the front ones would pop on and go off on their own a couple times during those few weeks.

First steps we checked all fuses and relays. No issues found. Pulled down the blower resistor and checked the blower motor and it still worked.

We then decided to order a new resistor. When it arrived the voila it started blowing air out the front vents again!

I thought we fixed it. Nope! About 1 week after replacing the blower resistor I had stopped at a corner store and when I shut my vehicle off the air kept blowing.

Turned the truck on and off again, took the keys out and still stayed running. I had to go inside so I thought maybe once I arm the alarm it'll stop then. NOPE!

Get home and still the same issue. Vehicle was off, the alarm was armed, and it still was blowing air. I knew I couldn't leave it that way, so we opened it up again and proceeded to remove the new resistor.

Next day we got the old resistor out of the box and took some contact cleaner to it. Cleaned up very well so we decided to give it a try. Plugged in the clean original part and VOILA, like magic it began blowing air & it even shut off when we turned the truck off.

About 7 months pass and all of a sudden it starts acting up again. It wouldn't blow air out of the front vents every time it was turned on, but those back vents still worked like they were supposed to.

It's been a couple months now and it's back to blowing air sometimes. Never turns on when I power it on, just decided when it wants to while we are using the back vents.

Now summer is approaching again and this is a top priority for me since summertime in the Central Valley of CA can get very hot and miserable!

Please help me! From fuses on up what would cause this issue of front air not blowing but back air blowing as it should? I will go through it all, just need to know what would affect the front vents and what wouldn't!

For some reason I feel like maybe something is plugged up because for whatever reason it just starts blowing on its own while driving. To be honest, IDK, I'm lost! I would appreciate any and all advice on what needs to be checked. Thanks in advance. ☺