My 99 ranger is running great,,,no codes,,,no check engine light,,,but when running idle my AC clutch is kicking on and off with blower or heat or AC OFF...is this a issue or normal operation with blower and control off ?? It kicks on and off very quick,,,have not tried turning heat or AC on to see if it quits !!!Just need pointed in right trouble shoot direction if needed,,,is air gap to wide ??? just not a expert like Pawpaw LOl

 

wow no reply yet,,,hmmm

 

The AC clutch should only cycle on and off whenever the blower motor is on, in any mode selection. I'd definitely say it's not normal operation to be coming on when the blower motor is in the off position. Air gap shouldn't be the issue. I'm assuming there is some kind of electrical short issue? Sorry I can't be more help than that. I've got a 99 of a customer's sitting here for a couple more days if you need me to run out and check anything.

 

The blower motor is "ON" any time the function selector switch is not in the OFF position.

A/C Compressor operation is enabled any time the function selector switch is not in the OFF, VENT, or HEAT positions.

To determine if you have a problem or not, you first have to determine if the function selector switch is in one of the positions where the compressor is supposed to be operating. If it is, then you have a problem with how it's operating when it is supposed to be operating (most probable). If it's short-cycling when the function selector is in a position where is shouldn't be operating, you have a different problem (or set of problems).

The most common reason for an A/C compressor clutch to short-cycle when it's supposed to be operating is due to an insufficient refrigerant charge, usually due to a leak. The less common reason for short-cycling involves a high-side restriction or overcharge conditions.

You need to first classify the the symptom under the conditions it occurs, then act accordingly.

 

Yes, your compressor will cycle on and off whenever the selector switch is in any position other than "OFF". The compressor is turned on and off by way of the refrigerant pressure switch. If it is running when in the "OFF" position, your system may be low on refrigerant, the pressure switch is bad or has a faulty connection..

 

That is inaccurate, see above.

There's more to it than that. This is a PCM-controlled system that uses the pressure switch as part of its input logic and uses a relay to actually control the clutch.

If it's running in the "OFF" position, there is something shorted in the clutch relay or its control circuit, a "bad" pressure switch or low refrigerant cannot cause this symptom.

 

ok thanks i will check into it more when the weather gets a little warmer,,,i have not had the system charged since i have had the truck,,,,my guess is a leak and low on refrigerant ,,, will let everyone know what i find when it warms up a little,,,just a little chilly and rainy right now

 

The compressor is short cycling in cold temps to allow oil within the freon charge to circulate to keep seals in compressor from drying out. Totally normal operation. If it short cycles in summer and fails to cool then a recharge would be called for.

 

The laws of thermodynamics relating to pressure and temperature have the final say. If the temps are too low, the pressure will be too low to allow the cycling switch to close and compressor operation is inhibited when the mode switch is in any position where the compressor operation is otherwise enabled. That's why your owner's manual usually includes a notice that the A/C won't operate at outside temps below about 50°F.

 

That makes no sense as the A/C is on when in defrost/defog mode to remove moisture from the air being blown on the windows.

 

The AC is enabled during defrost. It's actual operation is either still allowed or inhibited by the pressure in the system. The static pressure of the refrigerant is determined by its temperature.

Please go read your owner's manual.

 

It was my understanding from the original post that the compressor is cycling on and off when the the system is "OFF". If this is the case, anything having to do with normal AC operation is out of the questions. Not an undercharge, overcharge, pressure sensor, short cycle, none of this.

 

The OP's provided information is too ambiguous to draw any definite conclusions except that it is an illogical state; he REALLY needs to VERY CLEARLY state the circumstances of the concern. You may notice that he was asked to do so several days ago and so far has ignored that request.

 

I only drive the truck a couple of times a week if that ( short trips ),,,i will double check it next time i drive it,,,i am almost sure it is low on refrigerant and my neighbor has the gauges to check it,,,will post and let everyone know what i find soon,,,,just been to busy to mess with it right now,,,i have only used the AC once since i have had the truck,,,it blew cold air but not ice cold then and that was over a year ago,,,my money is it is low on refrigerant,,,,will hook gauges up when i have more free time

 

OK my mistake,,,I did have the heater on in defrost mode. I turned the control to off and drove a few miles to store and no clutch kicking .Drove home and left truck running with heater to feet and vents and clutch kicks on and off every 7 seconds !!!! It was 61 degrees out and was a steady 7 second on off,,,is this normal or is it probally just low on refrigerant ???? Sorry thought it was off in early post and it was in first position passed off