i have a 2000 f250 reg cab 5 speed w/5.4 gas motor, i have tried to get my ac to work but no luck. wanted to see if some of you folks could help. the system had around 85 psi static pressure, i bypassed the low & high switches with no luck. i have not tried to jump the compressor itself. pulled enough dash to see that the switch on the dash is vaccum operated with no electric. i did notice that the red tube runs to the engine compartment to a switch labeled evaporator service port 1psi max and have no idea what it does. everything i've tried wont start the compressor. any help or advice will be greatly appreciated.
jhooks4851

 

The "1psi max" service port is for the EVAP system and not related to the climate control at all. It's easy to get crossed up when tracing hoses or wires.

Since you've jumpered out the Low and High pressure switches,
Start the engine and turn on the AC. Tap the compressor clutch face with a screwdriver handle and see if it engages. If so, the compressor clutch gap is too wide.

If it doesn't engage,
- Check for 12v and Ground at the clutch connector
-Check for 12 V at one side of the Low Side Pressure Switch connector,
then post back with your results.
A 12v test light is fine for those tests. The actual voltage isn't important as long as the lamp lights up fully.

 

i checked the low side switch has power on one side the clutch does not have any power. thanks for the quick response to my question

 

You should probably read the FAQs (above) first...

 

Yeah, there's that, too .
I've seen it so often that I forget it's there. Duh.

 

i am new to this site and really dont know what you are suggesting i do or where to go do it. the only reason i came to this site was because it came up in my web search. if you dont want to help an old man out just say so and i will move on to some other place. i am just a beginner when it comes to places like this one so forgive me if i dont get it right. i am one of those old folks that was brought up to believe i should help others and i do when i can. you guys have a good day and thanks again for what info you gave me.

 

No, jhooks,
It's not that nobody wants to help you.
The symptom you describe is very common and can have a multitude of causes, most of which have been covered here many times and would take a lot of time to type out again to cover all of the possible causes.
projectSHO89 is suggesting that you first look at a really good FAQ (Frequently Asked Questions) post, which is the second posting in this sub-forum, that outlines a lot of basic troubleshooting steps and may answer your questions.
You can find it here: https://www.ford-trucks.com/forums/7...xpedition.html

If that doesn't help you or if you don't understand something, please feel free to post back. FTE is full of folks like yourself who want to help others. That's why they all hang around this online "old time corner garage".

 

Hmm. I'll have to dig out my 2000 Service CD and see how that clutch circuit is wired.

 

does it have any freon? if not thats why

 

thanks so much for the extra info. i just thought i might be out of touch with todays mechanics. i am one of those folks that believe you cant fix it if you dont try and dont like giving my hard earned money to dealerships since their rates are way to high. i pulled a wiring spec off of the mitchels web site and will start running the circuits down and will post back if i find the problem as it may help someone else. again thanks so much for the info i'll check that also.

 

By the 2000 MY, the AC clutch had moved to a PCM-controlled relay to energize the clutch.

The series circuit of the mode switch and the high and low pressure switches serves as an AC DEMAND signal to the PCM. The PCM, unless inhibited by operating conditions such as a wide wide open throttle, will energize the relay and switch power to the clutch coil to energize it.

 

OK forgive me if this has been addressed already, I have a 1997 f-150, The AC has not worked in several years and decided to start getting it worked on. SO I put freon in it one day and low n behold it was blowing cold. shocking! I inherited this truck after my mom passed away and my pops said it wasn't working. so anyway it worked for a couple of weeks and then stopped, started blowing hot air. checked for leaks but did not find any. so after a couple of weeks of trying to get it to work (just by turning it on and off), it kicked back on one day. so it worked for a day or two, i happened to be getting on the freeway and had to gun it to not get hit by another vehicle, well after I did that the ac went out and never came back on. After talking to pops he told me that the compressor was shot(bearings were bad) and that's why it works off and on. SO last week I finally got the cash and had the compressor replaced, they recharged the unit and everything. it was blowing cold air and I was happy, well besides the fact that the air was coming out of the bottom, (the mechanic said the actuators were bad and he could rig it to come out just on top all the time). ANYWAY! it worked for a couple of days and one morning I got on the freeway and well I had to punch it to avoid an accident (i Live in CC, TX, that should explain a lot LOL)well the air coming out got hot and after about a day it started to start coming out cool but not cold. the mechanic kind of explained how when you punch it, it automatically shuts the compressor off but is supposed to cut back on, well he is saying it is not kicking back on all the way. has anyone else experienced this and what worked for you? I am desperate and not too much money so I am trying to fix this myself. THANKS EVERYONE

 

When it's not working after you punch it, have you looked to see if the compressor is actually turning or not?

 

​​​​​​Well a day later, the mechanic looked at it. Said it was on and freon was good. That's when he told. Me about a relay. But I don't think this truck has one. But idk

 

This truck doesn't have an AC clutch (or any WOT clutch control) relay. The compressor clutch is controlled directly by the low pressure cycling switch. The mechanic needs to look it up next time so he's not giving incorrect information.

Check the blend door, it may be broken and flopping around with acceleration and stopping. Also see HVAC FAQs, link is in signature below.