Afther I did the DS II Swap...the A/C/Vents are NOT working...where does the vac hose that go from the A/C Control Panel through the firewall go??

 

To the distribution block up high on the firewall or to the vacuum reservoir depending on what engine.

(my 460 has no juice can or plastic ball)

 

Its in my sig, but I should have said I have a 4.9. No juice can. Does the vac line go into the vac tree near the carb??

 

It usually goes thru the 3 way connector up near the hood on the firewall, before going to the vacuum tree on the back of the intake. But it needs to make it's way to that tree somehow.

 

I'm not so familiar with the vacuum lines of an inline-6.
I do think the three port plastic 'log' is present on all F/U series.
There is no splitter up by the pinch weld?

 

I do have a vac hose coming through the firewall under the heater box from the heat/a/c panel...I'm just not sure where its supposed to go?!

 

There are two hoses coming out of the firewall. One (Black) is vacuum going IN to the AC control switch, the other (Black/White) is vacuum coming OUT connected to the vacuum (recirculate air) valve on the heater box (just above the blower motor).

The vacuum line coming off the intake manifold must have a check valve in it, otherwise the vent position would change to (default) defrost every time you went WOT. All of the setups I've seen use a can or ball shaped vacuum tank too. Maybe there are some factory setups with this tank.

 

Spot on! Best description I've seen of the system in a while.


FWIW, I repped ya for it. Finally found someone I could actually rep......

 

Well, like I said the a/c and vents worked before the DS II swap. I only see a black hose coming through the firewall under the heater box (its not connected to anything)...it cam unhooked from wherever...does anyone have a diagram...do I need to add something because I removed the computer??

 

If that hose is not hooked to anything, then somewhere you also have a vacuum port or line that is open. Find it, and make two meet.

No need to add anything, unless you took out the softball sized vac canister that is supposed to help run the HVAC system. In that case, you need to add it back.......

 

I did the swap a few months ago...so I did have to plug a bunch pf vac ports on the vac tree near the carb. I guess I'll have to see which one it fits. I'm not sure where the canister is (I didnt remove it for sure). I'm familar w/ the juice can size one...I dont have that.

 

Here you go. Hope this helps. Note that the vacuum comes from (page 92) the "vacuum distribution block" this is a three port tee (usually mounted to the firewall near the evaporator housing). The center port goes to the intake manifold (where the power brake booster connector is located), the left port goes to the A/C heater "R" (page 82) in the diagram below, and the right port goes to the automatic transmission module. If this manifold block/tee broke somewhere in the past the previous owner probably recreated it with some fittings, etc. so it may not be on the firewall anymore. The bottom line is that you need manifold vacuum to "R" and a check valve in that hose.

 

Sorry Sean, I'm not seeing your sig in the first posts of this thread.

CB, I would Rep you too, but I must like your posts too much!
There should be a vacuum motor at the recirc door on top of the heater plenum near the PS hood hinge.

But there must be a vacuum line going to either the reservoir or the distribution block (as is my case)
These plastic lines become very brittle and you might have broken it off without knowing Sean.

 

Very nice shot from the EVTM CB!

This is a good reason that each of us should have this manual for our year of truck.
They are only $10-20 delivered from Ebay.

 

That's better!! I still don't see where 2 different lines are connected (or should be connected). Again, I only have one black line coming through the firewall. I just wanted to get a jump on working on this later today or tomorrow.