These cars came either with the motor system, or the cable system, it seems at random! I thought that the 86 535i had the cables (mine does).

Anyway, regardless of the cause of your problem, here's an easy solution.

First, if you have the cables, just fix the cable, or get back there and manually pull it closed.

If you have the motor, you probably have a dead motor or a few broken teeth on the gear.

First, move the slider to the closed position. Get under the hood and remove the blower fan. Turn the power on (not the engine! just the power) and reach into the hole behind the fan. You should be able to lift a flap that's at the bottom side of the hole. If your motor is working, and there are just a few teeth missing, the flap should move closed on it's own. You may want to try opening and closing it with the lever (it may have just been stuck) but if it sticks again, don't open it again, and leave the lever in the closed position! If your motor is dead, you may be able to just nudge it into place and leave it. Leave it shut. You'll lose the fresh air face vents (use the windows!) but both your AC and heat will work a LOT better!

Mike L
I took my father's 86 535i to our BMW mechanic in the hopes of him being able to solve an annoying problem...the center slider vent control no longer opens or closes the center vents, and it appears that those vents are stuck open. The result is cold air from the outside blowing in through the vents in front of the A/C motor (the one below the heater and A/C controls and above the ashtray). The mechanic told me that to fix the problem he would have to take the dash apart and the job would probably take a whole day, thus costing a fortune in labor plus whatever parts needed to be fixed or replaced. He suggested a cheap solution of blocking the unwanted cold air flow by patching the area with a plastic bag and tape (he has done phenomenal work on the brakes on our 535i and my friend's E34 in the past, so I trust his opinion). I tried this but the cold air is just diverted elsewhere, now it is flowing through the gaps around the radio and through the space around the shift lever.

My question is whether it is possible to close the vents manually somehow, bypassing the slider control and the motor (i assume) that it is connected to. Any suggestions would be helpful..thanks in advance and Happy New Year!

-Francis
1986 535i