2001 Excursion A/C issues, need help, have gone bald with frustration

[Texas EX 7.3]

This started when I replaced the heater water control valve and snapper the MAP sensor vacuum port off last week. The A/C was already starting to cool poorly, but the compressor clutch was working. I can't imaging how these could be related.

Repairs so far:
1. Replaced the hot water control valve and MAP sensor.
2. Check the A/C and the clutch was not engaging
3. Had a small hole in the rear pressure line where the spring mount rubbed through. Removed, repaired, reinstalled.
2. Replaced the orifice tube with a new variable one while the system was down. (It is already hot in Texas)

Current Issues:
1. The compressor clutch was not engaging before the problem. Air gap is .028
2. The compressor clutch will not engage unless I put volts directly to it.
3. Tried jumping the high and low pressure switches - nothing
4. Checked the fuses I can find that are related #24 on the interior fuse box and #502 A/C Clutch Diode in the engine bay. Are there others?
5. Voltage with my volt meter seem to vary and I am not sure what is correct. .5-7 Vdc on the pressure switches and intermittent on the clutch.
6. Recharged, with jump wires to the compressor, about 68-70 ounces of 134a my low pressure is about 59 and my hi side is about 225-250. Adding more freon raised the low side to about 65, so I am not thinking that is helping. I know the low side should be in the 40s but it is just idling in the driveway.
7. Not sure what to do next.

[Texas EX 7.3]

My volt meter was reading intermittently.

The #24 fuse in the interior box literally fell out. When I opened the panel the 10amp hit the floor.

Everything works now!

[lug]

What was the OAT when you serviced your Excursion? I'm guessing it must have been close to 105-110 F outside to nail the pressures you listed for the low.

[Texas EX 7.3]

It was about 96 degrees outside that afternoon. I think I am slightly over charged. From what I have read, static pressure should be similar to the ambient air temp. I was at 100 static today and the ambient was 93.

[lug]

Good find on the fuse. That makes life much better. At 96 F the range is 30 to 45 psi on the low and 175 to 275 psi on the high. The closer you get to 30 psi the colder your ac will be and it will bring down your high pressure.
That 30 psi (low side) is perfect all the way to about 97.5 F, from there to 100 F it rises to 37 psi. The upper side is 45 psi to 97.5 F, from there to 100 F it rises to 60 psi. Keeping your pressure within the operating zone results in a center register discharge temp range of 34 to 47 to about 92 F and then it curves up 37 to 52 at 100 F.
You can check your efficency by measuring the temp at the center register. Set to 1500 RPM, MAX AC and blower on high. Using another temp gage take your reading on the center register when the cabin settles between 70-80 F. In your case you may need to use the rear A/C as well to help cool the SUV down faster. It's always nice being in a freezer on a hot asphalt melting summer day.

[Texas EX 7.3]

What are your thoughts on the static pressure to start with?

I was running about 50 degrees through the vent. That is currently the best I can do. That was driving down the road at about 40+ mph for a few minutes.

[lug]

Well if your outside temperature was close to 100 F then that may be the best your truck can do. If your truck came with a temp gage that tells you the outside temp I would use that as a reference number unless you know that its wacked. You can figure out the temperature spread and adjust from there. If it was 96 when you were driving 40 you are at least getting a 46 degree drop in temp which is better than having the windows down.
I would try at some point to get some freon sucked out, but if your happy with it then it can wait. The important part is you got your a/c back especially on those hot humid Texas days.