AC/Heater/Defroster vent selection

[Grumpy Dwarf]

Anybody know anything about the AC/Heater/Defroster vent selection? Right now mine is in the defroster only mode and when I select the floor or the dash vents it doesn't change. Blower and cold/hot selector works fine I just can't change where it's going.

Oh ya it's on a 99 TJ.

[Guest]

Mine too. Must be a 99 issue.

[tuffnutz70]

nope...my 92 xj is the same....no matter what the selection, only blows on defrost.

[rrock]

One thing that can cause that is the vacuum canister being disconnected. Or there could be a vacuum leak in the system, the vent selector is vacuum actuated, well atleast on the XJ.

[Grumpy Dwarf]

I found the problem with mine! There is a hard plastic vacuum line that runs from the throttle body, across the firewall over to the passenger side of the jeep and then into the cab. Mine was broke, must have broke it Saturday when I was working under the hood as it worked fine before that. I fixed it with some rubber vacuum line that I got while at the automotive parts store and presto......... it's working fine again. From what I can gather if the vacuum line is not the problem then it most likely is the vent actuator under the dash.

[t-rav_12]

Had the same problem with my '86 xj. Plugged the black plastic vacuum canister back in and fixed it right up.

[rjh]

that little nipple on the throttle body is a 90* elbow on mine. It tends to wiggle loose. It controls the vent selection and cruise control (yes, I have both A/C *AND* cruise *pffft*).

a tiny plastic zip tie has held it on nice and tight for ~3 years now. :)