Left front vent
 

Wanting some help on 1991 190E. Can anyone give help on the procedure for removing the left front vent in the dash. The lever on mine doesn't work. It's just loose. Thanks

I just did this on both sides of my '93 190E. You will find out that the plastic stub is broken and the lever is doing nothing. After I removed both side vents, I drilled a hole where the plastic stub should be. I used a smal screw and lock nut to hold the lever assembly in place. You have to line up the gears before inserting the screw and tightening the lock nut to adjust to the desired pressure.

To remove side vent, pull the vent out using needle nose pliers starting on one side. You'll see that the vent snaps back in.
Then, you'll need to slightly lift up the plastic tabs, 2 on bottom and 2 on top, to pull the assembly out.

On the left vent assembly, I removed the courtesy light rocker switch first.

So, on the left vent remove the courtesy switch first, and then you can remove the grill out of the vent next. Finally lifting the tabs inside the vent frame up and pulling it out. I wasn't sure if it would come out or not without pulling the instrument cluster out or at least a ways?? Thanks for the help!

The grill needs to come out to get good access to the 4 tabs.

Then, I removed the light switch so I wouldn't pull on the wiring when I pulled out the vent assembly.

If necessary, you might have to pull the cluster out just slightly for the left vent. I removed my left vent the same day I removed the cluster and I was able to pull it out before removing the cluster.