HELP--WOT or WTF ? 96 Ranger A/C

1996 Ford Ranger XLT ext. cab, 2.3 ltr. pwr steering, 5 speed, 55k miles. the a/c has full charge and is not leaking. the comp. keeps cycling every 10
seconds or so, not long enough to really cool things down, but cool none the less. wot switch? or wtf? any help would be much appreciated.......t.j.
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TJ wrote:

You know it's fully charged how? The low pressure switch (LPS) cuts off the compressor clutch power at 22~25 psi and won't allow power again until the pressure builds back up to about 45 psi. Constant cycling at short (10 second) intervals usually indicates low refrigerant, where 20 sec~30 sec intervals are normal. Check the low side pressure and if it's within the above ranges, the LPS is suspect. Test the LPs by jumping the LPs connector with a piece of wire.
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TJ wrote:

TJ, How do you know the system is fully charged? It sounds a little low. R-134a systems on newer vehicles have a smaller capacity and just a few ounces will cause this exact symptom. The charge amount is pretty critical. A couple of things to check, though; Is the interior fan working properly on all speeds? Is there good airflow out of the vents? Is the blend door (hot-cold control) working and adjusted properly? A down and dirty check is to see if the accumulator is cold and sweating (condensation) with the engine at high idle. If so, it should be cooling pretty well. To check the refrigerant system correctly you need to know both the high and low side pressures along with the ambient temperature. Also need to know if the lack of cooling happens at idle\low speed, cruising speed or all the time. The low side gauges from the parts store really don't tell you anything useful, if that's what you are using. Another often overlooked part is the engine cooling fan clutch. A weak clutch will cause poor cooling at idle and low speed and ocassionally compressor cycling due to high head pressure. At 1500 RPM the fan should pull a LOT of air through the radiator\condenser. Check the easy things before you start chasing electrical bugaboos that probably arent there. There is no WOT switch, just a high pressure cutout and a low side cycling switch. They do fail but not very often.
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Thanks for the responses everyone. The pressure was checked with one of those red/green/orange gages from advance auto, the kind attatched to the can, it read green so I did not charge it. great airflow from the vents, cold too, for a few seconds. Blend, hot cold working well too. Also sweat from the accumulator. it seemed to start out as a problem just at cruising, idle would run comp. always, but now its also cycling at idle too. Fan clutch is drawing ALOT of air. I just replaced the original battery with oem battery (9.5 yrs on it). But this problem was in the works before I replaced it. Thanks for any help.......... T.J.

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how do you know it's at full charge?
how do you know it's not leaking? Did you test it with a sniffer? or just look for oil traces... not a sure indicator!
You say it cycles every ten seconds... do you mean it's off ten and on one second or less?
If so... almost surely low on refrig.
But you didnt mention the low side gauge reading during this cycling... which brings us back to "how do you know..."
There is no WOT switch, that comes from the PCM logic, reference the TPS and maybe the MAF. If the cycling is at a steady rate, that's ruled out.
To illuminate the other two answers...
It only takes a couple tablespoons of refrigerant to have the pressures seem normal in the static (not running) state. That's how A/C works!
I disagree with the need for a full set of gauges to remedy the possible problem... but ONLY if you understand the physics on how your A/C works.
Which, if you are going by the static pressure, you dont.
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Yes, system has been checked with sniffer.... T.J.

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