1999 T/A HVAC Switch Issue...HELP!

[ws6speedpaul]

I have a 1999 WS6 T/A and when I select between defrost, dash outlets or feet outlets the air is not directed to the area which I select anymore. The airflow is currently stuck & is split between the defrost and feet, but no dash airflow.

Everything worked fine until this morning.

Can any tell me what tha issue may be? Need a new control switch or something other.
What needs to be removed to get to the back side of the switch panel?

Thanks in advance for any help you can give me.

Thanks, Paul

[Injuneer]

Usually its a problem with the vacuum that operates the flapper doors. The check valve in the system often cracks and breaks. Shoebox has a diagram of the system and a photo of the check valve for a 95. You car should be essentially the same:

http://shbox.com/1/hvac_vacuum.jpg

The check valve will be on a vacuum line, passenger side, near the firewall.

http://shbox.com/1/vac_check_valve.jpg

[ws6speedpaul]

That is probably what the issue is since I was replacing both heater core hoses this past weekend (which are on the RH side) and may have broken/detatched it. The controls were working fine before I replaced the hoses.

Thanks, Paul

[Injuneer]

Following up on your private message, I do not know exactly where the vacuum line connects to the manifold on the LS1. I really haven't worked on many of those.

[ws6speedpaul]

Thanks for the response Fred.

I literaly laid over the engine bay and stuck my hand all the way back to the firewall where the vacuum line was attached to the wire harness. Mind you this was all done without line of site.

I found the open end of the vacuum line and felt around for a nipple on the back of the intake manifold, which I did find. It took a little time, but was able to blindly re-connect the line to the nipple and the system works flawlessly now.

Thanks for your help on this one!

Regards, Paul

[Injuneer]

Thanks to Shoebox!!!! He's the one with all the good documentation.