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So I have a 2002 F-150, 4.6L that only blows air out the defrost vents. Can not get it to cycle, found on the web that this is a vacuum issue.
Problem is I cannot find a vacuum line into the firewall where I would think it should be by the battery on the passenger side. I have found this elbow here the previous owner put a screw in but can’t find it’s counter part
Does your AC not work or does your vent control not work?
If if you have eatc, the O-rings in the control head are what often leaks and prevents it from controlling where the vent is.
Does your AC not work or does your vent control not work?
If if you have eatc, the O-rings in the control head are what often leaks and prevents it from controlling where the vent is.
But you also mentioned cycling....
All I know it will do it blow air (not cold) through the vents only. The blower motor works as far as speed (1,2,3,4) but no matter where you have the direction for vents it is only through the defrost vents at the windshield.
I figure a/c needs a recharge but I wanted to figure out the direction of airflow first.
From what I understand the vacuum line that comes off the check valve at the passenger side of engine bay, on the bottom of the T should run into the fire wall for the vent control?
All I know it will do it blow air (not cold) through the vents only. The blower motor works as far as speed (1,2,3,4) but no matter where you have the direction for vents it is only through the defrost vents at the windshield.
I figure a/c needs a recharge but I wanted to figure out the direction of airflow first.
From what I understand the vacuum line that comes off the check valve at the passenger side of engine bay, on the bottom of the T should run into the fire wall for the vent control?
Both vents and blend door are controlled via eatc if you have the electronic control.
Leaking orings in the eatc can basically shift vent and blend door to what you describe. Sometimes it can come and go, or goes under acceleration when manifold vacuum is less.
Is this new to you so you suspect no vac supply at all?
Both vents and blend door are controlled via eatc if you have the electronic control.
Leaking orings in the eatc can basically shift vent and blend door to what you describe. Sometimes it can come and go, or goes under acceleration when manifold vacuum is less.
Is this new to you so you suspect no vac supply at all?
I have the *****, three ***** :speed,temp and position. I’m not sure if this changes that?
I can’t dei
I have the *****, three ***** :speed,temp and position. I’m not sure if this changes that?
I can’t dei
There's two black vac lines that route in that location. One would be the front axle breather tube, so make sure you don't have that one ( I don't think you do) the other comes off a T/check valve. That's your engine side source vac and AC reserve. It routes through the firewall to feed the servos. The firewall grommet would be behind your hand in the picture. That said, that black line you have in hand SHOULD come from the T check and run inside that cab for the AC to function properly. It relys on vacuum and reserve air to function properly. Looks like your going to need to locate the other half, that will be fun. Perhaps you can find it just on the other side of the grommet if you fish around for it again. If not...well, there isn't an easy way from this point.. pulling the glove box out completely may help.
There's two black vac lines that route in that location. One would be the front axle breather tube, so make sure you don't have that one ( I don't think you do) the other comes off a T/check valve. That's your engine side source vac and AC reserve. It routes through the firewall to feed the servos. The firewall grommet would be behind your hand in the picture. That said, that black line you have in hand SHOULD come from the T check and run inside that cab for the AC to function properly. It relys on vacuum and reserve air to function properly. Looks like your going to need to locate the other half, that will be fun. Perhaps you can find it just on the other side of the grommet if you fish around for it again. If not...well, there isn't an easy way from this point.. pulling the glove box out completely may help.
this is what I have and where I expected to find the line for the dash to go through the firewall
That's the line alright. Yea, that's going to fun finding the other half..don't envy you lol. I've never had to yanked a glove box, or know if it would help. However, that's where the other half should be, behind it..in the vicinity anyway. You can lift the inspection cover off the top (center) of the dash and see what you can see from there first..if anything. Then perhaps dive under the dash to attempt to locate the black vac line that way as well. You know, to avoid pulling the dash apart if you don't have to.
Another option would be pulling the vac line from the destination point, with compressed air, shoot a little air through it, therefore locating roughly where the break is under there. That would give you a ball park idea anyway.
Another option would be pulling the vac line from the destination point, with compressed air, shoot a little air through it, therefore locating roughly where the break is under there. That would give you a ball park idea anyway.
I was thinking this as well, maybe hook a smoke pump to one I took a look at a customers truck to try and find it as well but couldn’t get in there on his. Will probably go to a junkyard local and start to take things apart to help see it
02-25-2019, 08:52 PM
Help me find A/C vacuum problem
