alnen

This is sound advice for any repair! I can't tell you how many times I've gone in just to buy a part, and the auto store people are 100% sure they know what the problem is, and I end up leaving the store with totally different parts going in a different direction (the wrong one). It doesn't cost them a dime if their wrong, but it sure does cost you or me a pretty penny. I no longer even listen to their advice, I have to politely as possible interrupt them and explain that I am not looking for advice. I already second guess myself alot of times with car repairs, I dont need the extra rabbit holes to follow!

Bennyv83

If your fan isn't working your low-side pressure will drop, and the low pressure switch will cut out.
High ambient temps will increase system pressure and may not drop the system out, especially with the fan working.
DO NOT mix the r134a in your truck with that max-cool or other crap the part store sells.
You truck takes r134 and that's all it takes.

It sounds like you are undercharged though, the fool at the parts store saying your suction pressure is at 55psi has no idea what he's talking about. Running, the suction pressure should be around 45psi.
Off cycle pressure will vary with outside temps, and underhood temps.

Do yourself a favour, take it to a shop.

nightowlll

ok I was able to take a quick video with my phone of what is happening with the compressor. I uploaded it to youtube. Take a look and let me know what you think. in this video it happens at around 11 seconds and then again at around 43 seconds. However, sometimes it does it very frequently, like every 3 seconds.

nightowlll

I appreciate the tips you guys. I had already bought the cycling switch that is on the passenger side of the engine compartment. So, I guess I will change that out and if it doesn't fix it I might go ahead and take it to a shop. I'm just low on cash from buying the truck and doing all of the repairs that I have done already and it has got me scraping the bottom of the barrel if you know what I mean.....

I always try to save some cash if I can trouble shoot it myself with the help of others like experienced people on forums like this one.

Your help is much appreciated.

nightowlll

this is the switch I purchased to replace.

sdmartin65

Some cars have a check valve behind that switch and some don't. Not sure about our f150's. But it empties the freon out pretty quick without the check valve. Sure someone will chime in about our trucks.

Just call me Sean

iTrader: (1)

I know I changed the dryer on mine, and I'm pretty sure it has the valve.

nightowlll

Im gonna change that switch this morning. Thanks for the info on the chech valve! I'll let you guys know how it goes.

nightowlll

Ok, well I changed out the switch and drove the truck for around 10 minutes and it seems to be working fine. No cycling on and off yet. Although, I think I need to drive it for around a half an hour to be sure.

Thanks once again to "Just call me Sean" and everyone else on here for your assistance!! This forum rocks!!

steve491

When you have it on MAX AC it recirculates cabin air, normal AC does not. The recirculating servo is in this picture circled in red. Ford is notorious for the little plastic vacuum lines dry rotting and falling apart. I looks like someone has already repaired your, but I would check it again.
FYI, when there's a huge vacuum leak in the HVAC servo system everything defaults to the defrost ducts. My truck used to do this under load when vacuum was the lowest.