Hello all:
I have a 99 Expedition Eddie Bauer edition 4X4 with the 5.4 Triton engine.

I am trying to add some coolant to my air conditioning system. I have purchased the kit, but for the devil of me, I cannot locate the low pressure port to add the coolant.

Can someone help me with this? I would greatly appreciate it.
Thanks,
Tom

 

The Bigger of the 2 hoses is your suction side , follow it,around , an you should find the fitting, if its color coded its a blue cap .

 

It might be a black cap, but no worries, low pressure fitting only fits that fitting. And if its out you probably got a leak and adding freon not going to last that long.

 

Hi:
I appreciate the effort, but so far you guys haven't been much help.

My brother and I ( and my brother teaches auto shop in a high school) have been all over and under the engine, but can not find the low pressure port. The top port is sitting in plain view and is very accessable. The location of the low pressure port remains a mystery. My guess is that it is hidden behind a panel or something and I would like to avoid tearing apart the engine on a scavenger hunt.

I am aware that the valve fitting on the recharge supply will only fit the low pressure port. That much was explained to me by the guy at the auto parts store (who also couldn't find the low pressure port).

I am also aware that there might be a leak, but the A/C does blow cold - it just takes a little while to get there. That leads me to believe that there is refrigerant in the system (not freon, but R-134), but it is low. In the long run, if and when I do find that low pressure port, I might discover that there is indeed a leak, but being a do-it-yourselfer, I am attempting to solve this problem at the lowest cost possible. So far, I have about $20 invest in a can of R-134. I would like to pursue this course of action until I am forced to do otherwise.

I was hoping that someone out there had actually recharged their A/C system and could tell me exactly where the low pressure port is.

Thanks again. If I happen to find the answer via another source, I will be happy to share the good news so we all have a little morei onfo on this site.

Thanks again for your help.

 

Facing your engine, look on the left side of the firewall. There will be a bracket that holds the vacume solenoids for the 4x4. Look underneath this bracket. You should see a canister(dryer) for the a/c. The low port is on this canister. Is VERY hard to see!

 

^ he is right! It is easier to remove the plastic cover to see it on the passenger side of the firewall. I had to do one before and took forever to find it.

 

he teaches auto shop and cant follow the ac lines!!!

 

I thought They removed the low pressure port so that we can't charge it. Only a technician can! You have to make a connection to the low pressure switch port. It"s better to go into the accumulator canister because you don't want to send liquid to the pump, so putting liquid into the accumulator canister insures that only gas goes to the pump!

I helped my neighbor on his Ford and we found if after the evaporators and before the accumulator canister "receiver dryer"
It's kind of hidden, in a hard spot to reach right agents the firewall on the passenger side!

going into the low pressure switch port would work but a custom fitting would have to be used!

 

 

The low pressure valve is indeed on the canister, but you won't see it unless you take off the low pressure sensor. Apparently whoever designed this AC forgot a low pressure sensor inline and just stuck one on the fill port. Seems pretty much like a bad hack to me, but that is what you have.

This sensor is a black plastic box about the size of a cigarette lighter with two wires going to it that is threaded onto the top front of the canister. Unplug the wire and then take the sensor off using a wrench (7/16", I think). This will expose your low pressure valve where you need to hook in your refrigerant fill hose.

This does present a problem though. The low pressure switch is a normally open sensor that is closed by the pressure of the system. When you remove it to hook up your hose, your AC gets a low pressure signal which causes your compressor to cut off. Without the compressor running, it is impossible to get enough refrigerant into the system.

The way around this is to jumper the two wires coming to the sensor with a short piece of wire. This will give the AC system an indication that pressure is OK while you fill it. Once you complete filling the system and it is cooling properly, unplug the jumper, screw the sensor back onto the port and plug the sensor wire back in.