Vacuum Controllers (HVAC Controls)

[fleming442]

Figured as much. Recap of where I'm at on the HVAC system.

-Tested all the vacuum actuators and they all hold vacuum perfect.
-Was able to re-built and get both existing vac switches to stop leaking.
-Bought a new 9-port ACDelco vacuum switch.
-Found that NOS ACDelco control panel on ebay if needed
-Still have a vac leak when pulling at the purple hose under the hood. Instead of the rapid leak it's now a slow leak. (white heater valve hose is capped off, I do not have a heater valve currently)

We're getting there.... Thanks for the help guys.

Have you made sure the connector behind the glovebox is tight?

 

[Gonzo1970]

Was it tough to get the 9-port out?

I never tried, I just know mine is leaking so I got the replacement.. havent put it in yet.

-Gonz

 

[69hurstolds]

Was it tough to get the 9-port out?

I never tried, I just know mine is leaking so I got the replacement.. havent put it in yet.

-Gonz

You got to pull the head unit out of the dash. On the back you'll find it. I don't recall how it attaches, but it's likely not too difficult. The two-port has a bolt. The 9 port might clip into place on the rotary lever.

 

[69hurstolds]

Looking at a picture of a vacuum control valve, it appears it has a leg on one side that has a cut out for a small bolt to hold it in place. Makes sense.

 

[FL85GrandPrix]

Both vac switches were very easy to get out. And I also have the glovebox out at the moment, so the vacuum hose connectors behind there is tight. None of the hoses look bad. Tonight I am plugging the purple/pink hose behind the controller and pulling vac under the hood. Isolating the main vac hose for a leak.

 

[69hurstolds]

One thing you MAY can do if the purple line has a crack in it somewhere, or split where it's leaking, is get some shrink tube for that size and lightly heat it until it seals. Maybe put a little sealer over the crack before heating up the shrink tube. Just ideas floating in my head.

 

[FL85GrandPrix]

Spent some more time this evening testing the system. FOUND THE ISSUE!!!!!! Removed the ECU and found the pink and white silicone tubes that plug into the firewall bulkhead loose. They looked to be originally glued into the firewall bulkhead fitting, but the glue let go and the hoses came RIGHT out. I cut about 3/4" off both tubes and re-inserted them with a little bit of blk RTV silicone on the outside of the tubes. Before RTV'n back together I vacuum tested the hose under the hood through the bulkhead and from the tube back to the controller. Everything was tight as a drum. I have litterally tested every possible compoenent on this HVAC system for a vacuum leak. I'm letting the RTV dry tonight and will vac test one more time and expect to be 100% good to go. I still have the ACDelco 9-port vac switch enroute to me so I will install it while I have the dash apart. And the 2-port vac switch tested tight as a drum again tonight.... that's the one I could not find a replacement for. So I think we're nearing the end of this fiasco. Oh, and tonight I found the temp control cable holder that snaps into the heater box broken. So I need to order a new cable tonight. This should conclude the sorting.

 

[69hurstolds]

Mike's Montes has the cables but not on his website, curiously.

http://rover.ebay.com/rover/1/711-5...0001&campid=5335822911&icep_item=382570739124

 

[69hurstolds]

Oh, and good job troubleshooting!

 

[69hurstolds]

Ah, but I see it's a repro at $50 shipped from him.

Dixie Restoration Depot has the same one for $40. Not sure about shipping though.