please help ac not working

[joe marshall]

ok guys new to the forum but really hoping yall can help i got a 2004 expedition we have been having issues of the ac working sometimes and sometimes not well now it will not come on at all ive checked the relay ive jumped the high pressure switch nothing changed i put power straight to the compressor and it fired right up its a brand new compressor it has Freon im at a loss any recommendations it is manual controls

 

[1955moose]

Sounds like you've done everything, good night, good luck! Alright now let's start. You mentioned you powered the compressor, you jumped the switch. Did you hook up a set of gauges to see what your high, and low pressures are? That's where you start, you may be low on freon. Is the compressor clutch kicking on/off correctly. Are your blender doors opening/closing ok? Is the condenser free of debris, and not clogged? You stated it was a brand new compressor, tell me you, or whomever Installed it, changed the receiver dryer at the same time? Sure hope so. Also was the compressor pag oil installed when the new compressor was charged with freon? Those are just the basics. I'm sure the more experienced AC techs here will have others.

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[joe marshall]

I installed it vacuumed it down oiled and everything got plenty of ice cube fluid 150 static clutch is properly engaging when I hit it with the power probe

 

[stamp11127]

Ice cube fluid - thats a new one!

150 static is too high unless the engine was hot or you're in the sun.

 

[joe marshall]

Engine hot in the Florida sun I don't seem to be getting power to the high pressure switch and no signal power to relay

 

[stamp11127]

Jumping the high pressure switch doesn't accomplish anything - they are normally "closed" and will "open" when they reach a set pressure point.
Check for power on the low pressure switch located on the accumulator, passenger side usually.

AC wiring diagrams attached:

 

[1955moose]

I'm enjoying my ice cubes right now! Got a double freon charge of Seagram's VO in mine. Temp here in San Francisco right now is foggy, about 57 degrees. Don't need the AC today. Yesterday I drove to Morgan Hill, there it was 94. AC worked great!

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[BRIANGEE]

As Stamp said, if no power at the high pressure switch go upstream a bit to the low pressure switch. If it's open then you wouldn't be getting power at the high pressure switch.

If your power and grounds are bad at the relay then you could just have a wiring problem. You should have two powers when you pull the relay: one signal power, one load side power. The other two pins should be grounds. If your control side power is not present check the 10amp fuse 33 first. Fuse 11 feeds the load side of the relay so check that while you're down there as well.

 

[1955moose]

On my 2000, the AC pressure cutoff switch opens above 445 psi, and closes at or below 260 psi. Yours may be slightly different.

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[stamp11127]

Another one that has gone "****"?

 

[BRIANGEE]

Another one that has gone "****"?

AC got too hot and evaporated him?

 

[stamp11127]

I'm looking forward to next summers AC class - I'm going to work in that the old refrigerant, r134a is commonly known as freon. But the new refrigerant - r1234yf, is also known as "ice cube fluid".

 

[1955moose]

That must be real fun trying to drive there in August in Georgia, with just the windows down. I'll bet back in the 40's, 50's, you guys rigged a lot of swamp coolers. Hmm, a mint julip sure sounds good right now! It's all this talk of ice!

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[SEPTIC PROFESSOR]

He took it in to the Ford dealership