Compressor not Kicking On During Charge
Thread Starter
Intermediate
Joined: Jul 2003
Posts: 37
Likes: 0
From: Wichita Falls
Compressor not Kicking On During Charge
Hi All,
Working to get my AC functional and am having trouble. Below is what I've done and facts about the car. Please let me know your thoughts. I suspect the low pressure switch is not getting satisfaction and thus is killing the magnetic clutch on the compressor.
Could the cans of 134A I bought have insufficient pressure to trip the pressure switch?
Thinking of jumping the pressure switch. I'd think this would isolate the reason for the non functional mag clutch. Additonally, it would prove the electronics and wiring to the compressor wire were all good and flowing current.
1990 C4
-Owned the car for a few month and AC has never worked
-Heat exchangers completely removed
-blower motor removed, as bought from PO the motor never worked
-fan shroud opening closed off
-964UK rear blower motor bypass electronics performed
-before evacuating system today, compressor clutch would engage but no cooling
-since 964UK electronics bypass for motor were installed the vent fans have functioned properly
-Today I replaced all o rings
-Today I replaced the reciever dryer
-Today I replaced the expansion valve with updated 95' 928 134A valve
-Condensor fan kicks on low when ac button is engaged.
-Hooked up a can of freon with an integrated gauge to the low side and with the car running I could not get the mag clutch to engage and it felt like the can was nto feeding the system.
-Checked for power at the compressor wire while running and got nothing.
-Checked the compressor fuse and it was good.
Thanks,
Joe.
Working to get my AC functional and am having trouble. Below is what I've done and facts about the car. Please let me know your thoughts. I suspect the low pressure switch is not getting satisfaction and thus is killing the magnetic clutch on the compressor.
Could the cans of 134A I bought have insufficient pressure to trip the pressure switch?
Thinking of jumping the pressure switch. I'd think this would isolate the reason for the non functional mag clutch. Additonally, it would prove the electronics and wiring to the compressor wire were all good and flowing current.
1990 C4
-Owned the car for a few month and AC has never worked
-Heat exchangers completely removed
-blower motor removed, as bought from PO the motor never worked
-fan shroud opening closed off
-964UK rear blower motor bypass electronics performed
-before evacuating system today, compressor clutch would engage but no cooling
-since 964UK electronics bypass for motor were installed the vent fans have functioned properly
-Today I replaced all o rings
-Today I replaced the reciever dryer
-Today I replaced the expansion valve with updated 95' 928 134A valve
-Condensor fan kicks on low when ac button is engaged.
-Hooked up a can of freon with an integrated gauge to the low side and with the car running I could not get the mag clutch to engage and it felt like the can was nto feeding the system.
-Checked for power at the compressor wire while running and got nothing.
-Checked the compressor fuse and it was good.
Thanks,
Joe.
Rennlist Member
Joined: Dec 2002
Posts: 1,082
Likes: 2
From: indianapolis
a/c charge
hi , correct me if i am wrong but i believe that there is a low pressure switch in the system in the event freon gets too low it will cut off compressor to keep it from destoying itself. when you drained the system completly you have to fool the switch by bypassing it to get the compressor to cycle again. where the switch is i do not know but this should put you on the right track.
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Rennlist Member
Rennlist Member
Joined: Jul 2003
Posts: 2,577
Likes: 52
From: Atlanta
You said it seemed the system was not taking gas. There is a schraeder valve in the service ports. Is there a valve depresser on your service hose to depress it? It should take about 1/2 can of freon to get the pressure high enough to operate the pressure switch.
It is hot in July in Kansas, so good luck getting it going..
It is hot in July in Kansas, so good luck getting it going..
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Rennlist Member
Joined: Oct 2002
Posts: 4,033
Likes: 26
From: Philly Area ----- George Washington took a dump in my backyard!
If you started to get some flow of gas into the system, then it stops, and the outside of the can is ice cold, then one trick for getting fluid into the system is to immerse the can in hot water. Also, since you are switching to 134, don't forget to add the correct oil.
To get the compressor to turn, even when the switch won't activate it, jumper the clutch wire with a HOT power lead.
Remember, when switching to R134, you use 85% of what it calls for FREON.
Good luck.
To get the compressor to turn, even when the switch won't activate it, jumper the clutch wire with a HOT power lead.
Remember, when switching to R134, you use 85% of what it calls for FREON.
Good luck.
Three Wheelin'
Joined: Oct 2002
Posts: 1,879
Likes: 3
From: Pasadena, MD - Land of Taxes
Originally Posted by dutchcrunch
hi , correct me if i am wrong but i believe that there is a low pressure switch in the system in the event freon gets too low it will cut off compressor to keep it from destoying itself. when you drained the system completly you have to fool the switch by bypassing it to get the compressor to cycle again. where the switch is i do not know but this should put you on the right track.
