vacuum line routing for defrost function

[MEANSTREAK K30]

OK, guys I have an 84 c10 that I have , getting it back together. Anyways, there is a vacuum line that is hooked to the heater/air controls that goes through the firewall on the passenger side, that the defrost uses to function right. In the engine bay, this line is just hanging there, not hooked to anything(was like this when I bought the truck). I was told that it is supposed to be hooked to the engine for vacuum for the defrost door to open. Does anyone have a link for a diagram or can provide pics of how there set up is on their truck? Can I connect it to any vacuum port and be good?I have done the internet search and did not come up with much. It is probably on the emissions label , but it is not there.

 

[MEANSTREAK K30]

Looks like I will have to bother the dork down the road , and look at his 85 to see what I am missing and what is routed where.THANKS

 

[livid4dirt]

You should have a vacuum canister near the fire wall. See image. That vacuum line you are talking about, hooks up to that. Then from the canister it goes to manifold vacuum.

 

[MEANSTREAK K30]

You should have a vacuum canister near the fire wall. See image. That vacuum line you are talking about, hooks up to that. Then from the canister it goes to manifold vacuum.

View attachment 207327

OK , thanks. The canister is MIA , so it looks like a junkyard trip is in order.

 

[diesel4me]

It'll still work if you hook up the vacuum hose to manifold vacuum,you'll just have to put up with the defroster door opening and closing when the vacuum drops off on a hard pull with the throttle open wide...the canister helps prevent that...
I've used canisters off other cars like older Lincolns when I couldn't find a GM one (I think GM cars used the same ones as trucks or close enough too)--the Ford versions look like a maxwell house coffee can,they can rust through so be sure it looks good if you go to use one of those..

 

[MEANSTREAK K30]

It'll still work if you hook up the vacuum hose to manifold vacuum,you'll just have to put up with the defroster door opening and closing when the vacuum drops off on a hard pull with the throttle open wide...the canister helps prevent that...
I've used canisters off other cars like older Lincolns when I couldn't find a GM one (I think GM cars used the same ones as trucks or close enough too)--the Ford versions look like a maxwell house coffee can,they can rust through so be sure it looks good if you go to use one of those..

THANKS A LOT !