Hi All,

Got my trusty 89 3.0 shorty - notice a problem with the vent, where sometimes randomly, I get nothing out of my vents, and then sometimes it will blow fine…

not the blower motor, since I can hear it working… vacuum line somewhere? but where?

seems random, but perhaps it dies away more when the engine is under load? doesn't always come back at a stop sign though either… so… not 100% sure

the AC works great, so I like driving it in the summer, but need this issue fixed - thanks!

 

Definitely a vacuum line. Look under the hood near the passenger side. There should be a couple of thin plastic lines that go across and in/out of the air box area. Those parts that are exposed to the under-hood area will get brittle with age and crack.

I usually replace as much of those lines as I can with rubber hoses. Then I tuck the remaining plastic lines into the grommets of the air box so they're no longer directly exposed to the under-hood heat.

 

Funny last night at 9 pm I had the same problem, front and rear blowers running, but no air. I knew what it was, so I opened the hood and both plastic vacuum tubes were cracked, and separated. They are brittle, cooked by engine heat. I made a temporary repair splicing sections of the plastic tube inside a Simply Green spray bottle!! Today I will replace them with rubber vacuum hoses.

 

In my case, the vacuum line going to the rear AC was also broken, so only the rear heater would run whenever I turned on the rear air. That line controlled the air door and the heater control valve.

 

Air condenser isn't running

On the off chance that your condenser isn't running, check the ability to ensure the unit is connected to. Provided that this is true, check for a blown wire or stumbled electrical switch. Reestablish the force and check whether it begins.

Another potential cause is an indoor regulator that isn't set appropriately. Bring down the indoor regulator by five degrees and check whether it kicks on. If not, the issue is likely a broken engine or compressor. You'll have to get proficient
fix that issue.


Insufficient air cooling

On the off chance that the focal ventilating unit doesn't appear to cool your home satisfactorily, begin by bringing down the indoor regulator five degrees. On the off chance that that does not alter the issue, you may have a filthy evaporator. Painstakingly spotless the evaporator and let it keep running for a couple of hours. On the off chance that the issue remains, it could mean you have a shamefully measured aeration and - -
cooling system.


Air unit runs however doesn't cool

On the off chance that your A/C isn't cooling your home despite the fact that it's running, you ought to at present check the indoor regulator. Next, investigate the condenser. Is it messy or blocked? Assuming this is the case, clean it and evacuate the blockage. The condenser can get to be hindered by tall weeds, grass or other airborne garbage.


Air unit stop on and over and again

This is another issue that can happen with a messy or blocked condenser unit, and also a grimy evaporator. More often than not, giving the whole unit a decent cleaning and evacuating any impediments will dispense with the issue.

 

Thanks Martin, but we're discussing the AC system in an Aerostar van with two separate evaporation units so it's a little different from the typical home AC that you seemed to have described.

In this case, the condenser is a big radiator that sits in front of the engine radiator. But you bring up some things that are worth looking into: Make sure the condenser is not clogged with debris, and that the fan clutch is functioning properly. These can affect how well the AC system cools.

Otherwise, the flow of cooling air can be affected by the fan, the air doors that are vacuum activated, or any obstructions in the air plenums, as described in previous postings.

 

Was this on mine.
There are foam gaskets in there, now old and nearly useless and with dried contact glue.
Rogue foam then randomly jammed up the door operation.

I (probably) accessed thru the dash top and tested for this by manually pushing and pulling on the rods and arms and met with unexpected resistance.

 

Hi All,

just an update, now I can't get vent or ac through the vents at all… Heat vent works fine… but not any air flow through the ducts up top.

I don't see or feel any cracks in those vacuum lines… I see the ones coming from the inside of the blower motor….

one goes to this metal vacuum looking device, and I think the other in going to the vacuum tree in the rear of the engine?

does anyone have an ac vacuum line diagraphm - it's 99 degrees out, and it would be great to be able to use my air.

Thoughts?
Thanks

 

Did you check the lines under the hood? Check out the picture posted by Jose in post 10 of this thread:

https://www.ford-trucks.com/forums/1...un-faster.html

The white/black and orange lines tend to crack up with heat and age, and cause the problems you describe. In addition to these, the rear HVAC system has a vacuum line as well. On mine, the hose that controls the heater valve under the van was also broken.

 

Test with a vacuum tool, they are called Mighty Mite. Visual inspection does not always reveal vacuum issues. Another way to test is by blowing smoke into a vacuum line. The smoke will escape at the point where the leak is. If no vacuum leak is found, the problem could be the Selector Switch itself or the vacuum line connections at the selector switch. I have a Vacuum Manual but it was for my 1986, I don't think it covers the 1989 model year. Based on how you described the problem at the start of this thread, it is the classic broken vacuum line leak. Does yovr van have Rear Cabin Air/Heat?? If YES. look under the van, driver's side, forward of the fuel filler, there is a vacuum line which connects to the Heater-Coolant Valve with a rubber elbow.

 

Using a hand held vacuum pump like Jose A. recommended is the best way to find a bad diaphragm in one of the damper actuators. You can tell by watching the gauge and the damper actuators if the system is holding a vacuum like it should. Any autoparts store should have them and I've seen them at Harbor Freight also.

 

yes, Harbor Freight has some cheap vacuum testers that do the job.

Last year the Selector switch in my 1997 started acting up too, I have a spare TEMP Controls pod and just removed and replaced the switch, it had a burned / scorched area behind it. The problem was resolved.