[Edison Carasio]

I seem to be having a problem with my heat and AC. It blows hot and cold, but it's only coming through the floor or windshield vents and not the ones pointing into the car. This is gonna be a problem when it gets really cold (especially with no rear defroster). Any ideas what this could be? Or am I just gonna have to yank the dash apart to see if there could be blockage some where?


HELP!

[TOM RENZO]

Check the vacuum supply and juice can for a broken line. The blend doors work on engine vacuum. When it does not have a vacuum supply it reverts back to defrost mode only. Hope this helps tom

[Edison Carasio]

Originally Posted by TOM RENZO

Check the vacuum supply and juice can for a broken line. The blend doors work on engine vacuum. When it does not have a vacuum supply it reverts back to defrost mode only. Hope this helps tom

I just called the mechanic and he said the same thing. He said if it's under the hood, then maybe $30 to fix. If they have to remove the dash, then $100+. Something easily fixable myself? Never repaired a vaccuum line before.

[SM90Stanger]

Originally Posted by Edison Carasio

I just called the mechanic and he said the same thing. He said if it's under the hood, then maybe $30 to fix. If they have to remove the dash, then $100+. Something easily fixable myself? Never repaired a vaccuum line before.

I have the same problem. Luckily I had to take the dash off anyway to paint it up and all. So I guess I am kinda lucky. I haven't really started looking into the issue...

Maybe someone can tell us where the vacuum box is? That would be super helpful!

Thanks, Steve

[Edison Carasio]

I've got the manual at home in the car (drove my Honda to work today). Wish I would have brought it so I could flip through it later

[NavySVO]

If you go online to Mustang Monthly, they did a write up last year on replacing the heater core for the '87-'93 model Mustangs. It shows you how to drop the dash correctly. They go from there.

[TOM RENZO]

Originally Posted by NavySVO

If you go online to Mustang Monthly, they did a write up last year on replacing the heater core for the '87-'93 model Mustangs. It shows you how to drop the dash correctly. They go from there.

Kurt i am from the old school of thought???? I remove bolts brackets arms and tie wraps untill the part either falls off or i can remove it. Then again I have an after SCHOOL apprentice. He works a couple of hours at the shop for extra credit. HA HA he comes in handy when those heater cores come in. Am i mean or what??????? Well i figure it this way. If he jumps right in he is interested if not he neads a new career??????

[NavySVO]

Originally Posted by SM90Stanger

Maybe someone can tell us where the vacuum box is?

The vacuum plenum is in the passenger fenderwell. Black bulbous thingie

[TOM RENZO]

Originally Posted by NavySVO

The vacuum plenum is in the passenger fenderwell. Black bulbous thingie

Totally correct just follow the vacuum hoses.

[NavySVO]

Here is where the line comes off of the tree @ the check valve. It is a nylon line vice a regular vacuum hose. You will see it go from here up the passenger fender and disappear into the wheel well where it goes to the reservoir.
The check valve itself is sometimes the culprit. It can be had in the HELP section at your parts store.