AC not working

[tilliepeople]

OK so its a Navigator not an Expedition
My AC is not working. I can see the clutch kicking in and out every couple of seconds
I am assuming that the compressor is seized but I thought I better double check before spending any money

 

[Hamfisted]

Do you have a AC pressure manifold set ? What are the high / low pressures ? I'm guessing the system is just low on freon. You can pick up a can with a hose and gauge on it at Walmart or Home Depot or any auto parts store and attach it to the low side and see if the needle is in the green band when the compressor kicks on. Squeeze the trigger on the gauge/hose adapter to refill the system. They just leak down over a period of time ( years...) and usually need to be topped off.


AC Pro R134 Recharge Kit at Walmart






.

 

[tilliepeople]

If it were just Freon wouldn't the compressor run all the time (with AC on)instead of constanly turning on and off

 

[Hamfisted]

No. There is a low pressure switch (located on the front expansion valve...) that breaks the circuit to the compressor clutch when low side pressure is pulled down below 22 psi by the compressor. Put some freon in it and see how it does.

 

[tilliepeople]

Thank you very much
I'll get a can of freon as soon as i get paid
I have never seen the clutch do that before.

 

[tilliepeople]

Well that didn't work.
I'm going to try the relay next but im not hopefull.
No I do not have a set of gauges but when i hooked up the charge hose it only showed 22lbs and when I started the ac it dropped to 18. Put in about 10 0z and it jumped to 90 while charging and back down to 25 when not.
Backed it off until it never went over 70 but still turning on/off every few seconds

 

[Hamfisted]

Probably still a little low on freon. A full set of gauges would really help.

 

[Copper93]

The A/C clutch is designed to cut in and out depending on pressure. Are you getting any airflow from the vents, defrost or floor? Is the air hot as if the blend door isn’t moving away from the heater core? Also, when the A/C is running does the cooling fan engage to pull air over the condenser and radiator?

 

[tilliepeople]

I have suspected the blend door because it is pretty warm blowing out but that would not make the pump kick in and out
I guess I will have to find a cheap set of gauges and maybe a small vacuum bulb and see what I can come up with
I have changed blend doors before and some vehicles are fairly easy and some are a pain in the butt

 

[tilliepeople]

Update
I put the rest of my can of refrigerant in then flipped the can over to make sure I had all the liquid stuff they put in these cans and left it run for awhile and low and behold I got cold air
At this point I am assuming it needed the lubricant they put in these cans
Just hope it stays working now