air wont blow out of vents .. only defroster, what could the problem be? how hard would it be to fix?

 

Defrost only is the default position when the HVAC loses its vacuum source from the engine. Follow the plastic vacuum line from the HVAC box (under the hood on the passenger side firewall) back to the engine to see if its cut, melted or unplugged. Also check the spherical plastic vacuum reservoir under the air filter box for damage.

 

might have something to do with vacuum lines. im not sure if your hvac uses them but that would be something to check. it is a default safety mechanism that if something like that would happen then the air is routed automatically to the defrost to keep the driver safe or sumthing of that sort.

check behind the unit itself. beyond that i dont know.

man bob, beat me to the explanation.

 

by chance do you have a pic of the hvac box?

 

You can't miss it. It's the big black box under the hood on the passenger side firewall. Look for a plastic vacuum line coming out of it. The vacuum line could have easily been disconnected while working under the hood.

 

Mine did that when coy destroyed my spherical plastic vacuum reservoir, it sucks. Lost the vac in the lines.

 

For some reason, my thoughts keep coming back to the "2001 front end conversion" in his signature.....

 

it wasnt working before the front end conversino.. i looked real quick but everything look connected as far as i could tell, im going to go more in depth tomorrow

 

Mine went out once and it ended up being a vacume plug that goes to the resivour ball.. might check that, its behind the bumper under the passanger head light

 

Crawl under the dash and see if any of the vacuum hoses are disconnected from the vacuum servos - I think there are 3 servos. There is also a multicolored vacuum harness that plugs between the underdash plenum and dash control panel. Having a leak under there might do the same thing.

I remember that!

 

Mine was the vacuum line the dumbass firestone tech hid because I caught him changing 5 plugs not 6 :)

ITS DEFINITELY vacuum related..
I do need to see another ranger to see wtf the routing on this line is though..
I know its not where I have it now...
Rand

 

i found this problem in th emustang 2day i dunno if its the same but on the 5.0 its on the top passenger side and ttheres 2 lines coming out of it

 

While we are on the topic - the relay near the unit on the firewall clicks and my a/c compressor keeps cycling the compressor clutch about every 45 seconds. this seems to happen even when I have the thing on fresh air only. Got any ideas?

 

i have a similar problem with my air, only while on MAX AC it will off and on switch the the defroster and then the front vents... Does happen on Regular AC though

 

That is tha AC Cycling Switch and it's purpose is to cycle the compressor off to prevent the evaporator coil from freezing up. When the possibility of freezing is gone, the compressor cycles on again. It is doing its job.

The frequency of cycling is dependent on several variables like interior temp, ambient temp, engine RPM and the amount of refrigerant in the system. A system that cycles on for just a couple of seconds at a time is probably very low on refrigerant.

You don't give any indication about what you're driving. If it is a late model Ranger, your compressor clutch should not engage when the mode selector is in the Off, Vent Only or Floor Only positions. The compressor clutch can be engaged by PCM control in any of the other 5 positions.

 

Sorry for the limited details:
1999 3.0 Auto 4X4 80k miles
I am kinda familiar with the system cycling but this is way to often
Going to have refrigerant checked/filled tomorrow. ANyone do this himself
or is it less hastle going to a grudge?

 

45 seconds is not too often for R134a. If it comes to it, you can recharge it yourself with a kit. But that would be a waste because it is leaking. Eventually, you will end up getting it repaired, evacuated and recharged anyway.