I only use the ventilation system for heat during the winter. Otherwise, I never use or access it. Is there any reason this vent needs to be open other than when accessing outside air? Is it ever open when using heat?
The reason I am asking is that one of the little brackets under the dash that opens/closes one of the vents broke off, and it's holding up a bunch of projects. I would like to just leave it and move on if I can.
VOILA! OK, for you out there struggling with this, I finally figured it out. First, I am a weekender mechanic that just enjoys Jeeps and working on them - I apologize for insulting you on here that are experts.
I have been complaining about my fan upgrade (the Chevy Blazer motor upgrade) for months, that it did not change air flow much. Yesterday, attempting to solve the problem above, I discovered that if the passenger vent is closed, and the cowl vent is open (feeding the heater), the new fan blows me out of the cab. The open passenger vent reduces flow significantly.
So, the answer to the above question is this:
1. The functionality of the driver's vent is irrelevant to heater functioning. If your vent is broken like mine, just secure it up underneath the dash and move on.
2. Pulling the "air/vent" cable halfway out opens the cowl vent, which supplies air to the heater/blower.
3. Pulling that cable all the way out opens the lower passenger vent, which aids only in venting in outside air, and diminishes heater capability significantly. In other words, you never need to do this unless you want to vent in air flow in the summer months.
Very happy about this. For the record, the difference with the Chevy Blazer motor upgrade is amazing.
Also, solution for broken bracket...I just drilled a hole in the little bracket and slipped it on the vent rod end. I'm going to see if they can just pop a little weld bead on the end to fuse them together without melting the whole area. If not, it's 100-mile-an-hour tape and moving on.