air wont blow out of vents .. only defroster
#2
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.
#3
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.
check behind the unit itself. beyond that i dont know.
man bob, beat me to the explanation.
#5
Originally Posted by wdstone
by chance do you have a pic of the hvac box?
#7
#10
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!
Originally Posted by rngprerunner
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
#11
#13
#15
Originally Posted by kimmer415
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?
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.
#16
#17
Originally Posted by kimmer415
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?
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?
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