AC/Heater Vent Problem

Hello everyone. I have a 99 gp gt with the digital dual climate control. Air will not blow out of the vents, hot or cold. All blower speeds are working correctly but the air will only come out of the defrost vents, changing the mode doesnt really do anything. I am wanting to fix this problem myself but I need an idea of where to start. Is it more likely that my problem is the control unit, some vent door thing, or somenting else? Any help would be greatly appriciated.

Thanks,

Sounds like the accessory vacuum needed by the HVAC system is missing. Check the vacuum line that comes off the intake manifold that loops around by the battery and engine compartment fuse box and then feeds into the firewall to a distributor block by the blower motor assembly. From there it branches out to the various actuators which are vacuum and electrically controlled.

BTW - A lot of times when the battery is replaced the vacuum line coupler located by the battery/inner fender gets disconnected.

This has happened to me a few times and the problem was exactly what Bob describes. I reconnected the vacuum line and all's well.

Thats exactly what my problem was. The line was rubbed through where it went by the battery. Thanks for the help. I wish all fixes were this cheap.

I wonder if this could be causing the interesting "groinka, groinka" sound I can hear in the cabin sometimes. Especially since I'm not getting great airflow either.

I wonder if this could be causing the interesting "groinka, groinka" sound I can hear in the cabin sometimes. Especially since I'm not getting great airflow either.

Probably not. When that vacuum line is messed up you normally do not get any of the center dash registers only defrost. Also, the noise you hear could be normal. When you adjust temperature in either manual or digital HVAC systems the temperature actuators may make a motor type sound or as you describe "grionka". However, it should not make that noise continuously. I'm assuming you have dual climate control digital since you have a GTP so there are two temperature actuators that may make noise depending on the temperature setting(s).

For airflow problems check for any debris or obstruction in the intake cowling and blower motor area. If you have a cabin air filter installed it may be clogged and just needs cleaning or replacement.

Hi Guys,
Had a problem with my 89 GP not going to vent and checked out the vacuum line by the battery and found it was broken! lossened the brace, took out the washer res. and used rubber line to fix and whoala, problem solved. Just wanted to thank ya'll. This had been driving me nuts for a week now.....

Mark
89 commuter GP
97 Crown Vic PI
90 F350 4x4

Hi Guys,
Had a problem with my 89 GP not going to vent and checked out the vacuum line by the battery and found it was broken! lossened the brace, took out the washer res. and used rubber line to fix and whoala, problem solved. Just wanted to thank ya'll. This had been driving me nuts for a week now.....

Mark
89 commuter GP
97 Crown Vic PI
90 F350 4x4

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