Ok first post so I guess I'll see how this goes
-Starting about a month ago AC started acting up as it would Intermittently start blowing warm air, probably around 20-30 min into driving it ice cold ac then bam. 80 degree air blowing through the vents-so I just started to dive into trying to solve the and first thing I did was hook up some gauges and check my pressures, which fluctuated 30-45 psi low side, 210-260 high side, this is when ac is working properly
-Next the pressures for when it wasn't working waited, watched my gauges as low side went to -90 psi and high side-110 psi- I next checked to see if the compressor clutch was engaged and it wasn't
- so I hooked up forscan to check if my low pressure or high pressure switch were shutting the clutch off-Shut off the truck, started it again and watched to check when the clutch disengaged and saw that when the clutch disengaged my high pressure switch shut the clutch off at around 230 psi- which it shouldn't- so I replaced the switch and now the switch works properly no longer shuts the clutch off at normal pressure-But now the clutch is disengaging with both switches reading properly, so another problem- Next I checked to see if it was a problem with the clutch it self and found through forscan that my computer said the clutch was engaged- but went down to check to see if it was engaged and it wasn't
* So my question is where do I go from here for my diagnosis, I'm confused as to why the computer thinks the clutch is engaged when it really isn't
- Any help is appreciated

 

Well, I would check the connection at the compressor and the harness for any chaffing. Both are known problems. Also, check the gape on the clutch. If it is out of tolerance that could also be an issue. B.

 

The clutch gap is easy to check with a feeler gauge and, if out of spec, easy to adjust with a spacer kit or if you have washers of the proper size (#4).

 

- Will Do, the thing that intrigues me is that it is so intermittent, I mean some days it won't even do it and on the days it does it is so random and starts working again randomly may take 1 min or it may take 10 min to start working again.I would of thought that if clutch gap is the problem that it would be constant, and for the electrical I would of thought that the computer would say that the clutch is not engaged if there was no power to it from electrical issues. Thanks for the advice I will be checking both sometime this week.

 

To my knowledge, there is no "feed back" sensor loop to tell the PCM if the clutch is actually working or not. It's just a plain electrical coil circuit. There is no year/make/model in your signature, so we are just making SWAG's. It sounds more like you have an intermittent connection, either of the Positive side or the Ground side of the coil. Good luck. B.

 

-Don't know how to edit my signature to display what my truck is, but it is a 2006 6.0 f-250 Crew Cab
To answer about the "Feed Back" Sensor loop, Through Forscan their is a command that lets me look at the clutch activation called ACC "Air Conditioning Clutch' and it's description says it displays the current state of the clutch, if it's activated or deactivated- I will update you sometime this week when I have checked the electrical part

 

Right. Forescan "sees" system voltage being sent to the clutch coil, but it can't see if it is going through the coil and coming out the other end. That's how I am reading this. I don't have Forescan so I am not intimately familiar with how it derives readings. B.

 

I'm not arguing with you. I understand what you are saying. B.

 

- Just to clarify on how to check the clutch Gap, I just stick a feeler between the Disk and hub Assembly- and the actual pulley when the truck is off correct- If so the reading is way out of spec at .060 in

 

You are correct. B.

 

- Thanks for the fast replies I will be correcting the gap later this week and will update the thread once I corrected the gap and tested it for a couple of days.

 

Go the very top the home page and look at the far top right. Left click on the down arrow next to your name and left click again on User Control Panel. That will take you to another page. On the left Side of that page look for Settings and Options and left click on Edit Signature. That will take you to another page where you can write up s signature. Have fun. B.

 

Let's say you are at your 0.060". Measure the washer(s) installed and correct off that. If the washer stack is 0.100" and you are at 0.060" gap, the washer stack needs to be 0.070" to 0.055".

 

- Just took the disk and hub assembly off and found one washer measuring around .030 in, took it out reinstalled the assembly and put blue loctite on the ac clutch bolt and tightened down reasonareasonably. The gap is now .032 in just barley out of spec.
-Two questions is their another way to reduce that gap to within spec. as their are no more shims or washers in it Or should I just run it .002 in out of spec and don't mess with it?
-Next question do you have the specific bolt torque for the ac clutch bolt?

 

You can buy the shims; they come in kits both Motorcraft and aftermarket. But they are 6mm washers of different thicknesses.

MOTORCRAFT YF1800A

The bolt torque is 10 lb-ft.

The gap will be OK for a while.