A/C compressor question

[kawasakiman27]

Hi all!

My ac compressor runs whenever I turn on my blower motor regardless if its heat or ac. Is this normal? I thought it was only upposed to come on during AC operation or defrosting operation.

 

[creepinjeepster]

No, your compressor should not run whenever the blower motor is turned on. It should run when in A/C mode, when in any defrost mode it should cycle on and off. Any other time it should not run. Possible faults could be a faulty pressure switch or even your A/C on off control may be faulty and no longer breaking the circuit to the compressor when in the off mode.

 

[kawasakiman27]

cool I'll check it out further

 

[TomB1269]

At tempatures below 40 or 45 I beleive the new A/Cs will not engage or only intermittantly, by design.

 

[kawasakiman27]

Ive heard that before. I turned on the heater the other day and sure enough the ac compressor clicked on and runs during heat op.

 

[creepinjeepster]

It will run in the heat op if in a defrost vent position. It is designed that way so that extreme cold on the outside with extreme hot on the inside of the window does not cause the window to shatter. That A/C cycles on and off to keep the heat from getting too hot. This theory is also proven easily when you have a chip in your window. Cold outside, get heat inside and chip turns into a crack.

 

[shadow6]

my ac pump runs regardless of what the switch is on, think i got the same problem you do.

 

[rangerjr]

on/off switch is bad he pressure switch is for he coolint in th system if there anit enuff coolent in the system it wont allow it to kick on or if there is to much it will o the something so u really have 2 presure switchies one on the high pressure side and low side i know for a fact.just rebuild a friends 3.0 about a month ago

 

[oldfordman]

I have a 99 ranger. Same thing. The A/C compressor runs in most of the positions, except for floor only and vent only. I have seen this mentioned in many posts, Ford designed them that way. Many manufacturers run the compressor in the defrost setting to keep the compressor lubricated by running it once in a while and it also removes humidity. However, Ford went way overboard. I plan to hook up a bypass switch so the compressor only runs when I want it to. Should help with the crappy gas mileage these things are noted for. As for cracking- in 50+ years, in weather from Georgia to Maine (-50 degrees) I have never seen a windshield crack from the heat of the defroster. If there were a crack already, I can believe it might widen it, but it would have to be so big that hitting a bump would do the same thing.

 

[triumphrider-1]

I have a 99 ranger. Same thing. The A/C compressor runs in most of the positions, except for floor only and vent only.

These are the two positions that the compressor will not come on.

 

[kawasakiman27]

cool! thanks for the info guys!