A/C cycling when selector in certain positions

[C.Steele]

This is probably a stupid question but it is something I have been wondering about for a while. My '95 did the exact same thing so I'm guessing it's normal, but I'm still curious.

Why does the A/C pump seem to kick on and off repeatedly ONLY when the heater selector (not sure the proper name) is in the defrost or floor/defrost positions? This happens even if the A/C is not on (like now in the winter) and only in those two positions. I can turn it to floor/dash, floor, and dash and it stops.

No big deal, just wondering why in those two positions only I get to hear *Clunk* tick *Clunk* tick as is cycles on and off every few minutes.

[maxwedge]

It is designed this way to de humidify the incoming air, usually this will only happen when the outside temp is above 40.

[C.Steele]

Ah ha! Thank makes sense. Thanks so much for the reply!

[j cAT]

Originally Posted by C.Steele

This is probably a stupid question but it is something I have been wondering about for a while. My '95 did the exact same thing so I'm guessing it's normal, but I'm still curious.

Why does the A/C pump seem to kick on and off repeatedly ONLY when the heater selector (not sure the proper name) is in the defrost or floor/defrost positions? This happens even if the A/C is not on (like now in the winter) and only in those two positions. I can turn it to floor/dash, floor, and dash and it stops.

No big deal, just wondering why in those two positions only I get to hear *Clunk* tick *Clunk* tick as is cycles on and off every few minutes.

when it is cold out the refrigerent is low in pressure . the low pressure switch as a saftey device shuts off the AC compressor to protect it from running with a low level of lubricating refrigerent/oil...

when the temps increase to 60 deg f and higher the properly charged system my still do this cycling but over a longer time period ..an example would be the interior of the vehicle has cooled down and you have reduced the fan speed to the lowest position ...this then would reduce the heat absorbed by the refrigerent droping the pressure..causing some cycling...

in defrost the a/c in on ...