Classic issue of AC Venting to Floor

[Drizan]

Hello,
I have a 79 El Camino with 350v8 (I attached a crappy photo of it since this is my first post and I know you might be interested). Previous owner (a friend so I trust he believes his claim) claims the AC was fixed but it sat for a while between that time and when I purchased it. Now that it is heating up here in AZ again I decided to fix the issue.

The air blows into the floor exclusively regardless of settings. The only thing that changes when I make changes to the control panel is fan speeds.

Vacuum is working under the hood and comes past the firewall. All actuators are working and the gates open when I apply vacuum to them but none of the gates open when using the control panel on the dash of the car with the car running. The middle gate that uses the blue line is the gate that needs to work to send air through my dash but like I said none of the gates are actually opening so obviously it is a problem. I did find a leak in the red heater line as shown in the picture which I have now patched. The issue is not resolved but I didn't expect that to be the issue since it was heater line.

The only thing I can think to try is cleaning up the HVAC control panel in the dash as it is quite dusty since I live in AZ and it also sat for a while. I am currently in that process now and if the issue is resolved from a good cleaning then I will let you know but until then I would love to hear your suggestions as I have run out of ideas.

It seems that vacuum must be lost from the time that it reaches the connection point behind the glovebox and the time the HVAC control panel sends the vacuum to the actuators since I know they work, their gates work, and I know there is vacuum behind the glovebox.

**If anyone knows where I can find new actuator nipple connection points and the clip that holds it to the actuator (the clear silicone thing that has a hole in it) I would really appreciate it as I would prefer to replace that if possible rather than just patching it. I don't even know the name of that part as you can tell so I can't search for it. Also that clip was missing on the car.**

Thanks

 

[69hurstolds]

Those factory clear silicon vacuum line nipples were factory deals. They had a loop on them to hook around the elbows of the heater pods where applicable to hold them in place so they wouldn't slip off. While not absolutely necessary, they were pretty handy to have.

The only thing I can think of is some aftermarket rubber boots. May can zip tie them on the actuator or something of the sort, but all I can find is some straight rubber nipples.

Sounds like you might have the 9 port vacuum selector switch rubber disc failure. Just a thought. Hopefully it's just a broken center pin. You can usually fix them with a very small machine screw and nut.

https://www.autozone.com/fittings-and-hose-line-connectors/vacuum-connector-and-tubing/p/dorman-autograde-soft-vacuum-tubing-connector-assortment-6-piece/426019_0_0?cmpid=LIA:US:EN:AD:NL:1000000:FLT:19489353541&&CATARGETID=120054150001289815&CADevice=c&gclid=Cj0KCQjww4-hBhCtARIsAC9gR3YvO-9q59pOfSZHMEcvSOqOnInkLJ4TTnJJys468Ks_gBkJrUC7XfgaAkAXEALw_wcB&gclsrc=aw.ds

 

[Drizan]

Those factory clear silicon vacuum line nipples were factory deals. They had a loop on them to hook around the elbows of the heater pods where applicable to hold them in place so they wouldn't slip off. While not absolutely necessary, they were pretty handy to have.

The only thing I can think of is some aftermarket rubber boots. May can zip tie them on the actuator or something of the sort, but all I can find is some straight rubber nipples.

Sounds like you might have the 9 port vacuum selector switch rubber disc failure. Just a thought. Hopefully it's just a broken center pin. You can usually fix them with a very small machine screw and nut.

https://www.autozone.com/fittings-and-hose-line-connectors/vacuum-connector-and-tubing/p/dorman-autograde-soft-vacuum-tubing-connector-assortment-6-piece/426019_0_0?cmpid=LIA:US:EN:AD:NL:1000000:FLT:19489353541&&CATARGETID=120054150001289815&CADevice=c&gclid=Cj0KCQjww4-hBhCtARIsAC9gR3YvO-9q59pOfSZHMEcvSOqOnInkLJ4TTnJJys468Ks_gBkJrUC7XfgaAkAXEALw_wcB&gclsrc=aw.ds

Thank you for the information and the link. I will be working on the 9 port vacuum selector switch and I will update this post if that ends up being the issue. Thank you again.

 

[brrian]

I had this issue & just fixed my vacuum switch. I grabbed two extra switches out of junkyard cars. I have an extra fixed one, pics below, if you're interested. If you do your own, use a little bit of silicone grease on the inner rubber part.. it seems to help it seal.

Also - there's a second, smaller vacuum switch on the back left side of the heater control. When you take your control out, check that one too. It can break too (mine was).

 

[pagrunt]

I had this issue & just fixed my vacuum switch. I grabbed two extra switches out of junkyard cars. I have an extra fixed one, pics below, if you're interested. If you do your own, use a little bit of silicone grease on the inner rubber part.. it seems to help it seal.

Also - there's a second, smaller vacuum switch on the back left side of the heater control. When you take your control out, check that one too. It can break too (mine was).


View attachment 218584 View attachment 218585

Which yards are you hitting down that way? It's been years since I've been to any city area yards other than the U-Pull It. I keep wanting to stop at that one between 130 & 380 on my route I take to get there but never have the time after the first (& only) yard stop.I know the really good yards by McKees Rocks are long gone.

 

[Drizan]

I had this issue & just fixed my vacuum switch. I grabbed two extra switches out of junkyard cars. I have an extra fixed one, pics below, if you're interested. If you do your own, use a little bit of silicone grease on the inner rubber part.. it seems to help it seal.

Also - there's a second, smaller vacuum switch on the back left side of the heater control. When you take your control out, check that one too. It can break too (mine was).


View attachment 218584 View attachment 218585

Thank you for the information and pictures.

 

[69hurstolds]

The little 2-port switch is for when you put the temp selector all the way to "cold". It allows vacuum (or vent, depending on the vehicle's NO or NC heater coolant valve)) to close the coolant control valve that's located somewhere in your heater hose setup. Anything off of full "cold" and the 2-port valve aligns to where the heater control valve will open.

 

[Drizan]

****Update****

Okay so I forgot to mention that due to another post on the forums about the issue the FIRST thing I checked after I knew vacuum was coming into the dash was the clip on the 9pin selector. It was intact however the SECOND I touched it with a screwdriver to try and pull the clip off to clean it it snapped. Like I pulled all the other clips as well on the whole thing when breaking it down and cleaning it up but that one may have already been broken but just barely holding on or something. Not sure if it was the issue but I did fix that clip that I broke by touching it.

Between that breaking and me fixing it and then taking apart the two electrical switches and cleaning them, then the two vacuum line connectors and cleaning those and lubing the rubber in them I have fixed the issue. So cleaning the control panel fixed the issue. That was my last ditch effort and I am glad it worked out.

I appreciate all of your responses. They really helped me out.

 

[brrian]

Which yards are you hitting down that way? It's been years since I've been to any city area yards other than the U-Pull It

HVAC stuff was UPull & Pay. One came out of the rusted out El Camino in the front of the yard & the other from a Delta 88 I think?.
Danser's on route 66 out past Blairsville - I want a Blazer rear sway bar & there are a few possible donors there but they're all on the ground.
Have you been to Millerstown Pic-A-Part? They show 2 GP's and a Cutlass in inventory. I haven't gone there yet.

 

[pagrunt]

HVAC stuff was UPull & Pay. One came out of the rusted out El Camino in the front of the yard & the other from a Delta 88 I think?.
Danser's on route 66 out past Blairsville - I want a Blazer rear sway bar & there are a few possible donors there but they're all on the ground.
Have you been to Millerstown Pic-A-Part? They show 2 GP's and a Cutlass in inventory. I haven't gone there yet.

Those have been the three I've been hitting for the past few years. There's Renicks up 308 past the Clearview Mall I've also hit.