NEED HELP AC works but not cycling off

nopaybob

Well-Known Member
#1
AC failed yesterday and would do the three blinks on the indicator when attempting to turn on.
This morning AC works, I hooked up a set of manifold gauges both low and high pressures look good. But I noticed the AC compressors not cycling off. The clutch only disengages if you turn the AC off.
Any knowledge or links appreciated. What could cause this? Is there a pressure sensor?


2010 Acadia
 

Drec

Well-Known Member
#2
Do you have a schematic? If you don't, you might check with your local library. With a schematic you could follow back through the circuit to figure out what is going on, or at least where the power is.
 

Mounce

Silver Supporter
#3
Would recommend a evac/recharge to check freon level. No way of knowing exact refrigerant amount without one. Morning is different temp than mid day and I'd bet it acted different throughout the day?

Just because the pressures were okay in the morning at a "cool" temp doesn't mean the levels are fine and it'll correspondingly react during hot Temps. Pressures are directly dependant upon outside air temp and fan function.
 
#4
What was the outside temperature? I know most modern vehicles prevent the compressor from engaging if the temps are close to and below freezing.
 

Wooluf1952

Well-Known Member
#5
I know the AC compressor will run if you have the Defroster selected. But I'm not sure if it cycles on and off like it does when the AC is selected or if you have both AC and Defrost selected.
 
OP
OP
nopaybob

nopaybob

Well-Known Member
#6
What was the outside temperature? I know most modern vehicles prevent the compressor from engaging if the temps are close to and below freezing.
It doesn't disengage

No problems until the froze up a few days ago When I put manifold gauges on
I know the AC compressor will run if you have the Defroster selected. But I'm not sure if it cycles on and off like it does when the AC is selected or if you have both AC and Defrost selected.
Would recommend a evac/recharge to check freon level. No way of knowing exact refrigerant amount without one. Morning is different temp than mid day and I'd bet it acted different throughout the day?

Just because the pressures were okay in the morning at a "cool" temp doesn't mean the levels are fine and it'll correspondingly react during hot Temps. Pressures are directly dependant upon outside air temp and fan function.
Pressures did increase as temperatures Rose through the day.
 
OP
OP
nopaybob

nopaybob

Well-Known Member
#7
There was a break at the condenser a few months ago. I replaced the part vac'd down and recharged. AC has been working trouble free for months until it froze up when the compressor stayed engaged and stopped cycling.
I didn't want to evacuate and recharge until I could figure out the failure
 
#8
Then your low pressure switch is probably not working properly to disengage the compressor. If the pressure gets low enough , it will freeze the system.
 
OP
OP
nopaybob

nopaybob

Well-Known Member
#9
Then your low pressure switch is probably not working properly to disengage the compressor. If the pressure gets low enough , it will freeze the system.
Will overcharge cause my issue with higher outside Temps? I did the repair in the winter and my second can literally froze removed frozen can and applied another so I had issues but it worked out and have been using the ac. But we just started hitting 90+. I purged a very small amount of freon yesterday with no change.
 

Members online

Forum statistics

Threads
18,384
Messages
562,815
Members
10,921
Latest member
samjamandham

Members online

Top Bottom