Hi guys, so I have a 2008 F150 XL 4x4 and I am having a.c. troubles. I'm going to start off with this. Last year I charged my a.c. system and it worked fine all summer, it even worked during the winter and it read normal pressure when I filled it then. Now as of recently it would turn on and sometimes stay on, or when I got to a light or idle it would stop and blow warm air, and now it's gotten worse. I can see that that the clutch is not engaging and all day yesterday 7/12/19 it would not engage all day, I got home, let truck cool for an hour and went out and tried it and it kicked on for a minute and shut off and hasn't engaged since, it's not making funny noises and the clutch seems to work when it wants to so I'm not sure if that is the issue. I have checked all the fuses(11,14,32)and relays and they are all good. I jumped the cycling switch at the a.c. accumulator and you could hear the relay clicking whenever you turn the a.c. on but the clutch would not engage. I only have a gauge for the low side and when I put it on it was reading warning in the red at about 90.(This is where I got in a argument with my father Mr.fordknowitall because I said I think it should read high because the compressors not cycling, and he said it shouldn't matter and that it's overcharged and to let some out) so I tried letting a little out to see if it would drop and it did not, it looked like it went up a little after. I'm kind of at a loss here now and need some professional advice going forward. Did I jump it in the correct spot? Is this a common issue? What do I do next? I'm going to head to the auto store and have them see if it's throwing a code of it they have a gauge for the high and low so I can test both and post what I find. I'm also going to mention I had 2 blow outs on the highway within a weeks period with Goodrich ko tires filled to 70psi They were older and getting worn so it did some damage to truck, but they both blew on drivers side front and rear, but it was acting up before then and I can't find anything damaged or that looks out of the ordinary around my ac system. Need to know what I should next please

 

If the compressor is not running, the low side should be the same as the high side. 90 sounds about right.

Even with gauges, the only way to properly charge the system is to evacuate it with a vacuum pump, then charge it with an exact weighed amount of refrigerant.

 

You can buy a cheap Harbour Frough vacuum pump for cheap. A lot of YouTubers use them for science experiments they are so cheap. But they do work.

 

Where do I vacuum pump it from if I need to go that route, I have a vacuum pump from harbor freight, I bought it when my 4wd vacuum line got cut by work buddy cutting my strut out when we did them. I was also told by someone and watched a couple videos about checking the gap between the clutch and compressor, honestly yesterday it looked like no gap, but I'm going to go buy a feeler gauge today cuz I can't find mine in my 2 garages full of tools. It's been in the 90's and I work in hot garages and outside all day and I need my a.c. before I get heat stroke lol

 

Pump it down from the high side.

 

This morning I was on my way to go get coffee and buy a new feeler gauge because I can't find mine, and I tried the a.c. and it has been working since and I tested the low side again and it had normal reading almost a little low from me letting some Freon out yesterday. It's been been turning on and off everytime I push the button in the cab, and it's blowing cold air like it should. I checked the gap on the clutch and I believe its .022 which should be normal. Could it be a bad solenoid cutting out? And where is the solenoid located, I can find it on the diagrams but not on the truck. Also I noticed the high side line is very warm, is that normal? The low is ice cold obviously and the drain isn't clogged cuz I get a nice puddle underneath from the condensation. I'm at a loss of what to do or test from here.

 

You need to get some gauges that read the high pressure side and low pressure side. The system is most likely low in refrigerant. Yes, you can charge it without removing all of the refrigerant if you have a good idea about what the pressures should be. I do it often on my truck since it has a small leak and it's cheaper to charge it occasionally instead of repairing it.

Reading the system pressure with the system not running tells you nothing unless it's completely empty.

 

There are no solenoids in the clutch portion of the A/C system.
Yes. You want cold on one side? Well, you're going to get hot on the other. Thermodynamics.

If it's working, there's nothing you can do except putz around and probably break something else. Wait for it to fail, then you'll have something to look for that can be fixed.

 

Yeah at this point I'm going to have to wait until it does it again. Is there another spot I can try and jump the clutch from? I tried from the cycling switch at the accumulator and I heard the relay clicking but not engaging the clutch. Also I noticed after unplugging the cycling switch that my check engine light came on. I knew it was from unplugging the cycling switch or so u thought so for ****s and giggles I went and had the codes read, I got codes, Fuel rail pressure sensor P0191
Scanner said Evap sensor PO453 but my book says its fuel tank pressure sensor circuit high voltage, and Evap system leak detected small PO456. Upon some investigation I found that when my rear drivers tire blew out last Tuesday the flap in my filler neck dislodged and fell down the neck, so I have a feeling that's causing the Evap leak code and the other Evap leak code from the gas cap not being tight enough. But the fuel rail code is throwing me off. They say that code is usually the fuel pump driver module which is also next to the tire that blew, but it looks ok and my truck hasn't had any shuddering or felt like it wasnt getting fuel. When my front drivers tire blew 2 weeks ago it also made my fuel pump connector thats under the drivers door come apart, and I reconnected it and taped it just to make sure it won't come apart. The check engine light came on after that but went away after like 100 miles and hasn't come back until yesterday.... any advice would be helpful, also if I need to move this part to another thread just let me know and I'll copy it to one about ODB codes or whatever

 

I would remove the FPDM and inspect the backside and the connector for corrosion. Remount it with standoffs.

 

If the codes don't disappear in a day or 2 I'm going to investigate further, for the heck of it though I will inspect the back of it, I think if I spray the nuts on it carefully it will come off easy and I can't put them back on easy and torque to spec if need be