vents not working, only coming out of defroster

[mnaemark]

My vents have not worked for about 5 years now and i finally decided to fix it now that i have my dash out. I dropped the heater box and found some broken vacuum lines coming from the climate control unit under the radio. Now that all that is fixed i realized that i was missing the vacuum canister from under the front bumper. Went to a salvage yard picked one up with 4 holes in it. Just wondering how to hook this thing up. I currently can only see two lines that need to go to it. A vacuum line from the intake and one going back to the heater box. i plugged the other two but this thing still is not working. Any help would be appreciated. And pics would be even better

specs
87 4.0 automatic

thanks
-Mike

[5-90]

You may have gotten a shonky "nothing tank" to start with. Don't suppose you plugged one port and pulled vacuum on another, did you?

As I recall, those things have two "sides" to them, with two ports to a "side." One "side" would be for climate control/HVAC, and the other would be for speed control/cruise control. Try the other side (although that may not work either - if the body seam is leaking, both sides probably won't hold vacuum...)

HTH

5-90

[mnaemark]

ill check that out i have a vacuum pump. Is there a different vacuum tank for cars with cruise?? I dont have cruise control so i dont think ill be needing those other holes

[5-90]

I don't think so - they try to standardise parts as much as possible.

This just seems like something I'd prefer to buy new, tho. You may want to check Summit or Jeg's - hot-rodders who like to run really "lumpy" cams usually end up needing some sort of vacuum reservoir, and I think I've seen them there before. I'm sure they had them for power brakes - but I don't recall if they had "accessory" vacuum reservoirs as well...

5-90

[Saudade]

The parts manual for my '88 makes no distinction with or without cruise. I have cruise so all of the ports on mine are connected. I think 5-90 is right about how it's split.

You could just blow in one port and see where the air comes out.

[mnaemark]

aha, figured it out with the blowing thing. I had all the hoses hooked wrong.

Thanks guys didnt realize there was more than one chamber

[lorax81]

i have the same problem but every thing is still hooked up what else will make this happen

i have checked all hoses
i have replaced the controller
i have torn my dash apart countless times and end up frustrerated