[Rock]

This car was recently acquired and evidence suggests that the previous owner did some extensive "rejuvination" work on it, like lots of new sensors and stuff, so I can't vouch for the car's proper connectivity in terms of the vacuum line. With that in mind, the Heating and A/C doesn't route the air to the proper dash outlets. It's defaulted to the Defrost.

If I force a vacuum on the little hose that passes thru the firewall to the HVAC, everything works fine. But placing the hose back on its connection (a little T-connection in another hose) results in failure. So I'm not certain that all the vacuum hoses are connected where they belong. I've scoured the FSM and I cannot find a vacuum diagram for where all the hoses are supposed to connect in the engine area

The HVAC Control Module diagram simply shows "to Vacuum Source" and I'm trying to determine exactly where that is.

Any ideas? I don't think all vacuum comes from one port since other items (FPR, EGR, EVAP) have separate connections to the throttle body.

Anyone got a diagram? If it's not in the FSM then I doubt one exists. Didn't they used to stick one on a decal in the engine compartment?
Thanks

 

[Krashed989]

I'm not sure about the correct routing of them, but if all else fails I would just simply add another T connection and some hose to make it work the way it is.

 

[Rock]

Sorry, I disagree with that solution because it doesn't fix the real problem. The real problem is why doesn't the hose have vacuum when it is apparently plugged on the right place? This leads to the need to verify the right place.

Is there a vacuum diagram available for this car?

 

[Ranger]

The "T" runs down to the vacuum reservoir under the battery tray. The vacuum source is on the intake manifold under the silver beauty cover.

 

[Rock]

Under the battery tray!? Geeze, now THERE'S a hiding place.
Thank you Ranger!

 

[WarrenJ]

Under the battery tray!? Geeze, now THERE'S a hiding place.
Thank you Ranger!

Well, there's SPACE under the battery tray. Surely you didn't expect them to leave it unfilled? It's a Cadillac after all!

Regards,
Warren

 

[87allante]

Thanks Ranger I have the exact same problem - couldn't find any specific info in the FSM, your post here saved me the rest of the weekend. I will get that hose connected tomorrow

Art

 

[Submariner409]

Now, THAT is digging deep for info!

 

[Ranger]

Kudos to 87allante. :thumbsup:

 

[aldedmon]

I have the same problem. I went to my local bone yard today and tore into a 98 to see where the green line that comeoff the Autorelease diaphram goes. Its part of a vacuuum harness that also controls the AC diverter doors. It crosses back to the passenger side behind the glove box easily accessible by just taking the lower cover from the passenger footwell, and then connects to a manifold tree that contains the other AC Vacuun hoses. They're red and yellow and green and blue maybe. The primary hose comes from the engine and T's off to go to the closed cylinder under the battery shelf and the other end comes through the firewall and and connects to the manifold. These lines are MADE into the manifold and cannot be removed / replaced. I had good vacuum from the engine to the T. I replaced the vacuum hose from the engine side to the T B/C it was fraile looking. My lower door actuator was / is not working properly and perhaps thats the cause of the vacuum loss. As stated I am getting vacuum to the manifold behind the passenger side glovebox but there is no vacuum in Park or Drive to the green autorelease line... Any one else have any ideas / suggestions

 

[Ranger]

My guess would be the problem is in the vacuum manifold by the glovebox.