2000 Century Vacuum Source for HVAC Dampers

[jwichman]

Please help, need to find the vacuum source that provides vacuum to the HVAC mode switch on the dash controls. My modes are stuck somewhere in the middle. I took the vacuum lines off the back of the mode switch, found no noticable vacuum at any of the lines. I then hooked up a small hand vacuum pump to each and found that the dampers move when vacuum is applied. Can anyone tell me where the vacuum source is for this control? Does anyone know where I can find a vacuum schematic diagram? Just prior to losing the vacuum control I heard a whine from under the hood. I switched the control from max ac to vent, shutting off the compressor, and the whine stopped. I returned to max ac and the compressor started again (no whine) but had no mode control. Any other thoughts?

[hdbones]

My 2000 Century had the exact same problem. After a little searching I found the vacuum line from the manifold into the passenger cabin had a significant hole in it. The hole was where the line passes under the battery. Looks like some acid from the battery ate thru. I cut the line back, reterminated it, and it works Great!!!!!!! Hope yours is as easy!!!

Originally Posted by jwichman

Please help, need to find the vacuum source that provides vacuum to the HVAC mode switch on the dash controls. My modes are stuck somewhere in the middle. I took the vacuum lines off the back of the mode switch, found no noticable vacuum at any of the lines. I then hooked up a small hand vacuum pump to each and found that the dampers move when vacuum is applied. Can anyone tell me where the vacuum source is for this control? Does anyone know where I can find a vacuum schematic diagram? Just prior to losing the vacuum control I heard a whine from under the hood. I switched the control from max ac to vent, shutting off the compressor, and the whine stopped. I returned to max ac and the compressor started again (no whine) but had no mode control. Any other thoughts?

[jwichman]

Originally Posted by hdbones

My 2000 Century had the exact same problem. After a little searching I found the vacuum line from the manifold into the passenger cabin had a significant hole in it. The hole was where the line passes under the battery. Looks like some acid from the battery ate thru. I cut the line back, reterminated it, and it works Great!!!!!!! Hope yours is as easy!!!

Any chance you know the exact routing of the vacuum line in question? I am having a hard time locating it. Where is it hooked to the intake manifold? If I can find one end of it in the engine comaprtment I'm sure I can trace it from there. I have found the other end in the passenger comaprtment, at the floor duct, unhooked it and found no vacuum. Thanks for you replies.

[hdbones]

If memory serves, its a 3/16" hard black plastic line, attached to the left side of the manifold with a rubber boot. It went from the manifold to the firewall, then under the passengers windshield wiper, attached to the RF fender, up near the battery, then enters a 2 inch wire loom
(with a whole bunch of other goodies) through the center of the firewall. The culprit was where the line leaves the fender and starts the bend back to the firewall. I think there was a rubber boot that aided in the speedy repair.

I'd send a photo, but I sold the car.

Originally Posted by jwichman

Any chance you know the exact routing of the vacuum line in question? I am having a hard time locating it. Where is it hooked to the intake manifold? If I can find one end of it in the engine comaprtment I'm sure I can trace it from there. I have found the other end in the passenger comaprtment, at the floor duct, unhooked it and found no vacuum. Thanks for you replies.